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Yard Track Spacing and Radius...

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Posted by richhotrain on Friday, August 6, 2021 7:07 AM

I don't have an absolute answer for you, but I can make some suggestions.

A minimum radius of 36" is great, especially on mainlines, but not really necessary for yards. What is more important on curves is the spacing between tracks, and 2" on center on curves is tight even though you are limiting your rolling stock to 40' and 50' freight cars. Spacing of 2 1/2" on center on curves is far better, at least in my experience.

Years ago, I got some good advice from my LHS guys about spacing of tracks on curves. They recommended that I buy a pair of 85' boxcars and test them on actual track to be sure. I wouldn't blindly rely on the advice of others unless they can say with certainty that 2" on center spacing for 36" radius tracks will work based upon their actual experience.

If this were my layout, I would use 2 1/2" spacing on curves and, since it is the yard, I would step down the radius on curved tracks to something like 32" radius. In fact, that is exactly what I did on my old layout where I installed a yard on a curve on my layout.

Hope this helps.

Rich

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Posted by Pruitt on Friday, August 6, 2021 9:03 AM

I have a slightly different perspective than Rich.

Large radius curves in a yard can really enhance the prototype appearance, I think:

 

 (pardon the bad white balance on that last photo)

The tightest radius here, the inside track, was 36 inches. Track spacing in the classification yard (the two innermost tracks were the mainline and the A/D track) was 2 inches. 40' cars were the max I had on the layout, but I think up to 55' would have worked fine too. Certainly there would have been no side swiping at that length.

On my behemoth helix on a prior layout, the innermost track was 36" radius, with 2" track spacing. Even 80' passenger cars did not sideswipe on those curves, though they didn't clear by a whole lot.

The biggest operational issue is how well the cars couple on curves in the yard. 50' cars on 36" radius curves should generally couple just fine without a lot of fiddling to align the couplers. If a little bit of fiddling is needed - say between a 35' tank car and a 55' mill gondola (even that shouldn't usually be a problem), well, that's just fine, IMO. Ever see a prototype switch crew have to fiddle with couplers to align them? I have...

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Posted by ATLANTIC CENTRAL on Friday, August 6, 2021 9:18 AM

I'm with Mark, bigger is always better.

On my new layout, the only curves less than 36" radius will be in some industrial areas.

My yard needs to handle every piece of equipment that would be on the mainline.

And with those curves, I have never used track centers wider than 2-1/8". Generally I have found 2" centers work fine for everything once you are above 36" radius.

Sheldon

    

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Posted by 7j43k on Friday, August 6, 2021 10:29 AM

Since the longest thing the yard will experience is a 65' mill gon, I am sure the 2" spacing is adequate.

Except:

Maybe not if you have to put your fingers between cars.  To make sure YOU are happy with the 2" spacing, put down 3 pieces of straight flex track at 2" apart.  Litter it with rolling stock.  Try fiddling with a flat car or two on the middle track while there's boxcars on the outer two.  How fun WAS it?

If it works for you then, 2" is fine.  This should apply to both the straight and the curved sections.

Note that the fewer derailments you have, the number of these possibly irritating events lessens.  Do good trackwork!  Fix your rolling stock!  Have fun!  Or else!

 

As far as the curves.  Radius is absolutely fine.  Keep in mind that the curved sections of track will "never" see coupling or uncoupling.  Cuts of cars will be pulled or shoved through.  Cuts of cars will occupy.  Or not occupy.  All of the "action" will take place on the straight sections of yard track.  

An exception, of course, is when a cut of cars has its end in the curve.  IF you then want to get at it from the other end of the yard, you'll be coupling on a curve.  I guess that's why they make bamboo skewers and extra arms and hands.  Actually, since you'll want to be aligning both couplers, perhaps a flat stick would work better--you can maybe shove both couplers inwards at once.

I can see there MIGHT be too little straight track in the first yard track from the left. I think I'd just live with it, if that's the case.

 

Ed

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Posted by ATLANTIC CENTRAL on Friday, August 6, 2021 3:47 PM

1.5" ? I think not. Trains are 10-11 feet wide, normal prototype clearance minimum is 13'-6" which translates into 1.86" is HO scale, or just under 1-7/8".

2" centers at 24" radius - that is trouble with long cars for sure. You have just been lucking as to brand, truck spacing, coupler setups, etc.

Sheldon

    

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Posted by 7j43k on Friday, August 6, 2021 4:34 PM

Sheldon,

I think you're in error in your correction to Mike.

If we take the car body width of an AAR standard box car, it is 9' - 10 3/8".  If we add 3" on each side for safety appliances, we get 10' - 4 3/8", overall.

That translates into 1.428" width.  In HO.

Which is certainly less than 1.5".  By a fair bit more than 1/16".  A hundreth of an inch, actually.

 

So you CAN use a 1.5" spacing.  Though you CAN'T put your fingers between cars.

 

But it's been pointed out by Mike that "there's no reason for derailments in yards."  So THAT'S not a problem.

 

You and I, perhaps not being as intellectually adventurous (that's not QUITE the phrase I was after) as Mike, might still go with that 2" that "everyone" likes.

I do confess that I'd like to watch Mike run his 1.5" yard for awhile, preferably with a beverage in hand.  Both his and mine.

 

Ed

 

 

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Posted by mikeGTW on Friday, August 6, 2021 4:35 PM

Sheldon 

Totally agree with what you state   I have three yards all are spaced 2" to 2 1/4"  so I took some track and put them on 1 1/2" center   NO way  cars would rub I physically tried different cars and most did rub to some extent

I didn't check my curves  but I have no problems with them

Mike

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Posted by mikeGTW on Friday, August 6, 2021 4:44 PM

Lastspikemike
Finally, we've found fitting an Atlas 9" re-railer sectional track into every yard track is a pretty handy place to rail a car for the first time on track. Retailing a derailed car in the yard is easier with one of these to access. These rerailers can be easily disguised as a road crossing. We fit ours all in a row in the yard so the road crossing effect is pretty realistic

 

You mention this club  You have never mentioned the name of it   would like to see some pictures of it   Is the club on line ?   

I know you either can't or don't know how to post your own pictures  so maybe the club

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Posted by ATLANTIC CENTRAL on Friday, August 6, 2021 4:51 PM

7j43k

Sheldon,

I think you're in error in your correction to Mike.

If we take the car body width of an AAR standard box car, it is 9' - 10 3/8".  If we add 3" on each side for safety appliances, we get 10' - 4 3/8", overall.

That translates into 1.428" width.  In HO.

Which is certainly less than 1.5".  By a fair bit more than 1/16".  A hundreth of an inch, actually.

 

So you CAN use a 1.5" spacing.  Though you CAN'T put your fingers between cars.

 

But it's been pointed out by Mike that "there's no reason for derailments in yards."  So THAT'S not a problem.

 

You and I, perhaps not being as intellectually adventurous as Mike, might still go with that 2" that "everyone" likes.

I do confess that I'd like to watch Mike run his 1.5" yard for awhile, preferably with a beverage in hand.  Both his and mine.

 

Ed

 

 

 

Again, prototype minimum track centers in present day are actually now 14'.

13' or 13'-6" was the common standard before that.

Current plate diagrams for cars today put 10'-8" as maximum car width over appliances.

That sure is between 10'-11' where I went to school.

Even in the 50's most stuff approached 10' over appliances.

Mike can do whatever he wants, but I'm warning others not to follow his faulty information.

Given the tolerances of NMRA standard wheelsets/gauge/track I would count on cars hitting each other even on straight track spaced at 1.5" centers.

But what could I possibly know after 54 years at this?

On the other hand, I also take exception to the idea of spacing track extra wide unless prototype info show it was done that way at a particular location you are trying to model.

Here in the east especially, land is money and railroads don't waste it.

Sheldon  

    

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Posted by 7j43k on Friday, August 6, 2021 6:37 PM

mikeGTW

 

 
Lastspikemike
Finally, we've found fitting an Atlas 9" re-railer sectional track into every yard track is a pretty handy place to rail a car for the first time on track. Retailing a derailed car in the yard is easier with one of these to access. These rerailers can be easily disguised as a road crossing. We fit ours all in a row in the yard so the road crossing effect is pretty realistic

 

 

You mention this "we"  You have never mentioned the name of "we"   would like to see some pictures of "we"   Is the "we" on line ?   

I know you either can't or don't know how to post your own pictures  so maybe the "we"

 

 

 

There.  I fixed it.  It's a bit clunky, but I got rid of that pesky club reference so that Mike can now respond

 

Ed

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Posted by 7j43k on Friday, August 6, 2021 6:50 PM

Lastspikemike

NMRA gauge is 2 3/16" wide.

I guess you are referring to THE NMRA Standards Gage.  It is not 2 3/16" wide.  Try again.

If 2" is enough on a curve then 1.5" is enough on a straight.

Right you are!  I pointed out that there is a whopping 1/16" to spare, if you run AAR boxcars.  If your car is 6 HO inches wider, things start to look really grim.

We use Woodland Scenics underlay which is 1 3/4" wide so our yard tracks are more likely 1 3/4" center to center and we can pick up a car when in the third track between two other cars on tracks. 

That's nice, but we're talking about 1.5".  So your 1 3/4" is irrelevant.  What is your experience picking up cars on yard tracks at 1.5"?

If you are getting derailments on straight tracks you need to relay your track or fix or throw out your locomotive or rolling stock. 

Right you are! 

I don't worry too much about actual measurements.

I don't doubt that at ALL.

I just lay the track down. I only know that it either works or it doesn't work. If it doesnt work I fix it.

It works.

That's totally marvelous.  I know I fix things that don't work, though I do try to do some measuring first.  I guess that's just my way, though.

" We" are not a club.

 

 
That's probably a good thing.
 
 
Ed
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Posted by selector on Friday, August 6, 2021 6:56 PM

To the OP, I suggest deriving empirical data. You have certain items of rolling stock.  They gotta work.  Right?  So, find out if they'll work down to a certain limit.  Get out a sheet of plywood or drywall, fix some track radii..nested to duplicate the conditions in your yard...and run a good sampling of your locomotives and rolling stock around them to see what happens. You'll find an empirical 'lower limit' above which you'll know to craft your curved yard ladders, and you'll construct them with confidence knowing your product will be satisfactory.  

This might take you all of 90 minutes, but my guess is it will be much less than an hour.  Be organized in your process and sampling, and then run it all using BOTH TRAILING AND SHOVING motions, as happens in a yard.

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Posted by SeeYou190 on Friday, August 6, 2021 10:43 PM

MSM
With yard spacing proposed 2” on center, using a minimum radius 36” will this be enough clearance to avoid cars from side swiping each other?  I’m modeling the 1950’s and most of my rolling stock is limited 40’ and 50’ cars (

Yes, you will be fine. the cars will NOT be side swiping each other. 40 and 50 foot freight train cars will pass each other on a 22 and 24 inch radius with no side swipes. Your broad radius curves make it even better.

Lastspikemike
2" on center curves works down to 24" radius for up to 85' passenger cars. No collisions.

This is 100% completely untrue. 85 foot cars will sideswipe each other on 24 and 26 inch radius curves on a 2 inch center.

-Kevin

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Posted by mobilman44 on Saturday, August 7, 2021 6:03 AM

"One size doesn't fit all"...........
While 2 inch spacing worked for me in the yard, it was tight for the ol "0-5-0" switcher to get to in some cases.  On curves, it took a bit of experimenting to get the spacing to safely have the long passenger cars pass each other.  IMO, the individual has to figure out what works best for him, and of course looks appropriate too.  

I've walked yards in Chicago (C&NW), Louisville (L&N, Durkee Foods), Joliet (ATSF, Durkee Foods, Mobil Oil) and Beaumont (Mobil Oil) and found the separation varied quite a bit - from room enough for an adult to safely walk, to big enough for a small vehicle.   

 

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

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Posted by richhotrain on Saturday, August 7, 2021 6:27 AM

selector

To the OP, I suggest deriving empirical data. You have certain items of rolling stock.  They gotta work.  Right?  So, find out if they'll work down to a certain limit.  Get out a sheet of plywood or drywall, fix some track radii..nested to duplicate the conditions in your yard...and run a good sampling of your locomotives and rolling stock around them to see what happens. You'll find an empirical 'lower limit' above which you'll know to craft your curved yard ladders, and you'll construct them with confidence knowing your product will be satisfactory.  

Agreed, and this is why I wrote my earlier response to the OP.

richhotrain

Years ago, I got some good advice from my LHS guys about spacing of tracks on curves. They recommended that I buy a pair of 85' boxcars and test them on actual track to be sure. I wouldn't blindly rely on the advice of others unless they can say with certainty that 2" on center spacing for 36" radius tracks will work based upon their actual experience.

If this were my layout, I would use 2 1/2" spacing on curves and, since it is the yard, I would step down the radius on curved tracks to something like 32" radius. In fact, that is exactly what I did on my old layout where I installed a yard on a curve on my layout.

Don't act on the advice of others unless they speak from personal experience. Try it out for yourself by putting down some track and running some cars. You are building a yard on a curve as I did on my layout. Spacing that works on straight mainline tracks is not the same as spacing on a curve, epecially in a yard where you are more likely to need to access individual cars.

Rich

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Posted by ATLANTIC CENTRAL on Saturday, August 7, 2021 8:58 AM

Mike, somewhere in all this most of us are trying to build a "model" of a railroad. Yes, that is full of compromises.

But looking to the prototype for operational standards is a good place to start.

The NMRA gauge is 2-3/16" wide BECAUSE, it is not a double track clearance gauge, there are pages of information in the NMRA Standard and Recommended Practices on double track spacing.

The NMRA gauge is a bridge and structure clearance gauge, and any simple reasearch will reveal that the prototype uses more generious clearances for trackside structures and bridges than it does for double track minimum spacing.

The pioneers in this hobby many decades ago adopted 2" track centers as a good compromise because it looked acceptably close, provided some extra clearance, and would work at least with larger curves as a single standard.

This allowed manufacturers to make lots of "compatible" products, double track bridges, turnouts, crossovers, tunnel portals, signal bridges and more.

You are obviously welcome to build your layout however you see fit. I personally would want no part of your seat of the pants, hook the flex track together before fastening it, way of doing things.

And I have been doing this successfully for a long time.......

I will stay with my universal 2" track centers, I will keep engineering the path of my trackwork before I install it, and I will likely leave you to it for a while, I have more important things to busy myself with.

And my 100 plus Atlas turnouts work just fine - maybe because they are properly fastened down..........

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Posted by SeeYou190 on Saturday, August 7, 2021 9:44 AM

richhotrain
Don't act on the advice of others unless they speak from personal experience

Yes +1

Anyone can read my posts, copy and paste them, and then claim that they are an expert.

Unfortunately, they are using my posts, which are not a good place to start.

Laugh

-Kevin

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Posted by hgodling on Saturday, August 7, 2021 10:52 AM

There is an NMRA RP (RP-7.2) to provide some guidance on this. The RP assume very large locomotives and 85' rolling stock, so it is probably a bit overconcervative. They recommend around 2.5" spacing for 36" curves. 

They do provide a tool to calculate the recommended spacing for your specific rolling stock. 

https://www.nmra.org/sites/default/files/standards/sandrp/pdf/curved_track_center_and_obstacle_clearance_assistant_jul_2017.html

Just playing with your rolling stock may be the easier route. However, for someone like me who is still planning and has limited rolling stock, these tools may be more helpful.  

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Posted by Overmod on Saturday, August 7, 2021 12:05 PM

Lastspikemike
Whatever works for any trackside obstruction has to work for passing trains. That's just geometry. Things either overlap or they don't.

The issue is that parts of the cars overhang inboard and outboard on curves, so the effective clearance between adjacent tracks becomes the most extreme 'worst case'.  You could build gages that would at least approximate this for particular types of car and particular 'sharpest' radii.

PRR discovered at some point that clearances on Horse Shoe were a bit tighter than the ones used for clearance in the J1 2-10-4 design, with the result that passing engines started trying to knock parts off each other.

There were some yards in the East with so little room between tracks that there would be damage if cars on adjacent tracks had plug doors left open.

It can't matter if only one of the things is moving or both are.

It does if the thing tips due to 'centrifugal force' far enough to make contact with another thing... or rocks with side-bearing clearance or offset weight... etc.

Part of the fun is that the force of contact (and many of the effects) increase greatly with relative speed.  At some point there might be aerodynamic effects that could induce deflection or rock.

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Posted by mikeGTW on Saturday, August 7, 2021 1:10 PM

Overmod

back when I started on RR about 197?   worked at Robert Young Yard in elkhart before I got on the GTW   anyway some of the tracks off of the hump were off limits to people they were so close together  If the cars rocked a bit they would hit I think they finally fixed them long after I was there

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Posted by ATLANTIC CENTRAL on Saturday, August 7, 2021 1:12 PM

And again, tapered wheels and and tapered axle ends do NOT insure that the car is ALWAYS centered on the track...........

Sheldon

    

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Posted by hgodling on Saturday, August 7, 2021 2:51 PM

Lastspikemike

To answer the OP's question indirectly the NMRA recommends wider track centres than 2" for reasons not clear to me.

https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7.1_tangent_track_centers_and_clearance_diagrams_2019.01.pdf

https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7.2_curved_track_centers_july_2017.pdf

https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7.3_curved_track_obstacle_clearances_july_2017.pdf

 https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7_track_centers_and_obstacle_clearances_july_2017.pdf

 One wonders why the NMRA gauge is set at 2 3/16" for measuring clearances. The clearances to track centres are 2.5" minimum for a pair of parallel tangent tracks. That's 5/16" wider than the gauge!

 

The NMRA RP actually says tanget (straight) tracks can have a spacing of 1 25/32" for cars of the "classic" era. (which fits the OP 1950s. 

 

The 2.5" spacing is for curved tracks. This is to account for the overhangs in the corner. They are assuming you have a big boy pulling 85' passenger cars so that is probably excessive. 

The standards gage is for straight tracks and is actually more for structures. Which have different clearence needs. 

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Posted by Overmod on Saturday, August 7, 2021 5:53 PM

There are few things sadder than when you try to help a dog and he tries to bite.

Lastspikemike
Centrifugal force would act on trains travelling on both the inside track and the outside track so the only effect of that would be the delta resulting from the differing radii. Pull the other one.
That would be true unless, um, the train on the outer track wasn't moving.  Which is where the concern is if you actually think about it a moment.

As we say in skeet, PULL!

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Posted by selector on Saturday, August 7, 2021 6:43 PM

Good lord, Mike....why not read and think a bit instead of scurrying over to your keyboard at every opportunity.

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Posted by selector on Saturday, August 7, 2021 6:46 PM

richhotrain

 

 
selector

To the OP, I suggest deriving empirical data. You have certain items of rolling stock.  They gotta work.  Right?  So, find out if they'll work down to a certain limit.  Get out a sheet of plywood or drywall, fix some track radii..nested to duplicate the conditions in your yard...and run a good sampling of your locomotives and rolling stock around them to see what happens. You'll find an empirical 'lower limit' above which you'll know to craft your curved yard ladders, and you'll construct them with confidence knowing your product will be satisfactory.  

 

 

Agreed, and this is why I wrote my earlier response to the OP.

 

 

 
richhotrain

Years ago, I got some good advice from my LHS guys about spacing of tracks on curves. They recommended that I buy a pair of 85' boxcars and test them on actual track to be sure. I wouldn't blindly rely on the advice of others unless they can say with certainty that 2" on center spacing for 36" radius tracks will work based upon their actual experience.

If this were my layout, I would use 2 1/2" spacing on curves and, since it is the yard, I would step down the radius on curved tracks to something like 32" radius. In fact, that is exactly what I did on my old layout where I installed a yard on a curve on my layout.

 

 

Don't act on the advice of others unless they speak from personal experience. Try it out for yourself by putting down some track and running some cars. You are building a yard on a curve as I did on my layout. Spacing that works on straight mainline tracks is not the same as spacing on a curve, epecially in a yard where you are more likely to need to access individual cars.

 

Rich

 

You were right on the money, Rich.  In a world governed by 'likes', I had merely hoped to offer reinforcement by posting my own version of the same idea. Cool

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Posted by 7j43k on Saturday, August 7, 2021 7:05 PM

Lastspikemike

 

Centrifugal force would act on trains travelling on both the inside track and the outside track so the only effect of that would be the delta resulting frim the differing radii. Pull the other one.

 

 

Nope.  Sorry.

You are wrong.  Wronger than Overmod said.

The whole point of bringing up centrifugal force here is that the train tips at a certain angle.  If it DIDN'T tip, what's the point?

For trains 1.5" wide, on parallel tracks at 2" centers, when the tipping angle from vertical is 42 degrees, they will touch.  I just did an experimental setup to find that number.

You, of course, will say that this is silly, among other reasons because they'd have derailed already.  Yes.  Quite true.  

But:

My POINT is that they WERE 1/2" apart when they were stopped.  To get to the above silly point, they have to move closer and closer as they tip further and further.  So, although they won't touch for sure until 42 degrees, the possibility that they MIGHT touch increases, too.

 

Let's see what happens when we close the track centers down to 1.6".  Standing still, they don't touch.  They're separated by .1"  But if they were to tip from centrifugal force, both going at the same speed, that .1" would DISAPPEAR at 21 degrees (experimental result again) from the vertical.  And, as pointed out above, the possibility starts increasing at earlier tip angles.

 

This effect is in addition to the difference of lean angle caused by differing radii.

 

Overmod, I trust you are getting my point.  Note that the trains are traveling at the same speed.

 

 

Ed

 

 

 

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Posted by SeeYou190 on Saturday, August 7, 2021 8:33 PM

hgodling
They are assuming you have a big boy pulling 85' passenger cars so that is probably excessive. 

My 2-8-8-4 will need to be restricted to the outermost of my hidden return tracks. The cab overhang is so excessive on the outside of the curve that this is necessary.

-Kevin

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Posted by 7j43k on Saturday, August 7, 2021 11:51 PM

SeeYou190

My 2-8-8-4 will need to be restricted to the outermost of my hidden return tracks. The cab overhang is so excessive on the outside of the curve that this is necessary.

-Kevin

 

 

Mmmm.  Me like!  Good!

(Sorry about letting my inner kid appear--it happens.)

 

Ed

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Posted by richhotrain on Sunday, August 8, 2021 6:02 AM

selector

You were right on the money, Rich.  In a world governed by 'likes', I had merely hoped to offer reinforcement by posting my own version of the same idea. Cool 

It just goes to show, Crandell, that great minds think alike. Yes

Rich

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Posted by Overmod on Sunday, August 8, 2021 8:19 AM

7j43k
Overmod, I trust you are getting my point.

I do recognize it.  You might draw a couple of diagrams to show why the interference develops as cars of roughly rectangular cross-section tip progressively around points corresponding to flanges on outside wheels, and then show the 'worst case' for sections at interfering ends on various car lengths, overhangs, and curve radii.

I didn't go into that detail as I was only concerned with potential momentary contact of a (potentially wobbly) car with a standing adjacent train with its now-fixed overhangs.  I think by the time we get to Unstoppable-grade levels of tilt, we're no longer in the realm of advice to the OP on reasonable track spacing for his purposes.  Even modeling of negative cant deficiency in passenger models (which Hornby did, and I presume Rapido did with their APT model) is on the esoteric side for typical modeling concerns -- although not for Amtrak on the NEC north of New Haven...

The other point in question is the wobble.  Yes, good models shouldn't wobble, but a good three-point side-bearing arrangement implies that the 'stiff' truck can prevent any roll of the carbody including when the 'far end' leads into what may be sharp curves and its angular momentum change is accommodated via the center pin of the 'tiltable' truck.  Long practical evidence with good model railroading practice certainly indicates this doesn't rise to the level of a chronic derailment cause, but in some cases, especially with sprung or 'articulating' sideframes, it might prove to increase the effective upper-outer 'critical contact radius' enough to matter if the situation were already critical.

All this palaver is fun but I don't think it's getting the OP much closer to what he was asking to know... Embarrassed

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Posted by 7j43k on Sunday, August 8, 2021 9:02 AM

Overmod

All this palaver is fun but I don't think it's getting the OP much closer to what he was asking to know... Embarrassed

 

Here's a bit more on the subject:

On a 38.5 inch radius curve, the tightest in the yard, a 65' long freight car (the potentially most troublesome) will project an approximate additional 1/8" inwards.  It will not project outwards that much.  Since there is 2" between track centers, and a freight car is about 1.5" wide, there is 1/2" available for clearance WITHOUT accounting for increased curve overhang.

1/8" is dramatically less than 1/2", so I say clearance in the curves in the yard for the type of cars and locomotives that will be in it is more than adequate.

IF projection outward in the curve were to also be 1/8" (which it will not), and two of these cars were passing, there would still be 1/4" clearance.

Note that no road engines nor passenger cars will be in this yard.

 

Now, the arrival/departure tracks might be different.  I see a 37" and a 39".  If an articulated is planned on being operated there, overhang outwards for the boiler front should be considered.  And perhaps outward overhang on each end of a 4-8-4.  Articulateds could be limited to the outer track, and likely things would be fine there.

I also note that two of the three A/D tracks don't have much straight near the switches, perhaps generating difficulties adding/removing engines and cabooses.

 

It would be wise if the OP were to do some overhang measurements and calculations for the "biggest" motive power and passenger cars on specified radii before locking things in.

 

I took a few minutes and found that the outward swing of a Big Boy's front would be a half inch on that 37" radius A/D track, so running such an engine on that track would not work out if there were cars on the next track.  In fact, if articulateds are contemplated on the layout, some double-checking all over might be in order.  For the A/D tracks, it might make it a fun challenge to limit articulateds to the outer of the three tracks.

Except for 89' flats, passenger cars are the big challenge on INWARD overhang.  On a 37" curve, they will come inwards about a quarter inch.  And less outwards.

Looks like the biggie on curves will be articulateds.

 

Ed

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Posted by SeeYou190 on Sunday, August 8, 2021 9:46 AM

Overmod
I didn't go into that detail as I was only concerned with potential momentary contact

This potential contact needs to be avoided because it will happen at the most fragile parts of detailed train cars. The corners and the center.

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Posted by SeeYou190 on Sunday, August 8, 2021 10:14 AM

7j43k

 

 
SeeYou190

My 2-8-8-4 will need to be restricted to the outermost of my hidden return tracks. The cab overhang is so excessive on the outside of the curve that this is necessary.

-Kevin

 

 

 

 

Mmmm.  Me like!  Good!

(Sorry about letting my inner kid appear--it happens.)

 

Ed

 

I am amazed by the Bachmann 2-8-8-4. It runs like a fine watch, looks good, and will negotiate a 22 inch radius curve.

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Posted by Overmod on Sunday, August 8, 2021 10:31 AM

SeeYou190
This potential contact needs to be avoided because it will happen at the most fragile parts of detailed train cars. The corners and the center.

Yes, a point I hadn't thought about.

I think Ed (and indirectly Mike) are correct about the relative unimportance of many factors on curved yard track spacing, including that nonprototypical articulated-locomotive outward overhang will likely be 'controlling'.

I'd be interested to know if the 'test' 86' boxcar has more inward interference than typical passenger cars -- likewise if 89' flats are in the same general category.

At least some of the changes to the NMRA 'gage' will be AAR plate changes over the years, with plate H now being common.  Do any modern Plate H models have more serious momentary-contact inside overhang than the old 86' boxes?

Here's Gritton's useful 'unified' plate reference again, through plate H:

https://gritton.org/greg/rail/docs/clearance/AAR_plates_with_UIC.gif

Note the 'kinematic' adjustments, but more importantly the AAR recommended clearance for Plate H.

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Posted by ATLANTIC CENTRAL on Sunday, August 8, 2021 10:34 AM

SeeYou190

 

 
7j43k

 

 
SeeYou190

My 2-8-8-4 will need to be restricted to the outermost of my hidden return tracks. The cab overhang is so excessive on the outside of the curve that this is necessary.

-Kevin

 

 

 

 

Mmmm.  Me like!  Good!

(Sorry about letting my inner kid appear--it happens.)

 

Ed

 

 

 

I am amazed by the Bachmann 2-8-8-4. It runs like a fine watch, looks good, and will negotiate a 22 inch radius curve.

-Kevin

 

But it has some serious overhang at that radius........

It just barely stays in the 2" track center window at 36" radius.

Sheldon

    

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Posted by SeeYou190 on Sunday, August 8, 2021 11:17 AM

ATLANTIC CENTRAL
But it has some serious overhang at that radius........ It just barely stays in the 2" track center window at 36" radius.

Yep, that is why the operational restriction to the outer hidden loop only.

As far as I know, this is the only piece of equipment I have with an operational consideration like this.

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Posted by 7j43k on Sunday, August 8, 2021 11:38 AM

When I said that a Big Boy would overhang outwards on a 37" curve by 1/2" (using up ALL possible clearance at 2" centers), that was based on a model locomotive with a non-swiveling rear engine.

 

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Posted by SeeYou190 on Sunday, August 8, 2021 11:51 AM

7j43k
When I said that a Big Boy would overhang outwards on a 37" curve by 1/2" (using up ALL possible clearance at 2" centers), that was based on a model locomotive with a non-swiveling rear engine.

Ed, I have compared two articulated locomotives, a Bowser 4-6-6-4, and a Bachmann 2-8-8-2. They have different designs. The Bowser has a rigid rear engine (prototypical), and the Bachmann has both engines able to rotate (non-prototypical).

I know a lot of this is apples-to-oranges, but this is what I have noted.

In prototype design, the boiler front seems to overhang a lot more on tight radius curves. With both engines rotating, boiler overhang is less, but cab overhang is increased.

Overall, both seemed to require a relatively equal side clearance.

Both of these locomotives would negotiate a 22 inch radius curve, and both looked completely ridiculous doing it.

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Posted by 7j43k on Sunday, August 8, 2021 12:12 PM

I'll note that my overhang dimension for the Big Boy was based on drawings of the engine.  With the normal slop in HO models, I wouldn't be shocked to find more.  Or even less.

I'll mention that 4-12-2's don't have this problem!

 

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Posted by ATLANTIC CENTRAL on Sunday, August 8, 2021 12:16 PM

SeeYou190

 

 
7j43k
When I said that a Big Boy would overhang outwards on a 37" curve by 1/2" (using up ALL possible clearance at 2" centers), that was based on a model locomotive with a non-swiveling rear engine.

 

Ed, I have compared two articulated locomotives, a Bowser 4-6-6-4, and a Bachmann 2-8-8-2. They have different designs. The Bowser has a rigid rear engine (prototypical), and the Bachmann has both engines able to rotate (non-prototypical).

I know a lot of this is apples-to-oranges, but this is what I have noted.

In prototype design, the boiler front seems to overhang a lot more on tight radius curves. With both engines rotating, boiler overhang is less, but cab overhang is increased.

Overall, both seemed to require a relatively equal side clearance.

Both of these locomotives would negotiate a 22 inch radius curve, and both looked completely ridiculous doing it.

-Kevin

 

I completely agree with that assessment and will add that as the radius increases, the double swivel designs have less front overhang, while the fact that the rear engine swivels becomes much less noticable.

So while it may not be prototypical, the double swivel design is a great appearance compromise even for those with large curves. It makes your large curves look larger.

All of my articulated locos are modern plastic/die cast double swivel designs and look fine on 36" radius and above.

The EM-1 is the biggest overhang offender on my roster.

The others:

Spectrum 2-6-6-2's

Proto 2-8-8-2's (now 2-8-8-0's)

BLI N&W A 2-6-6-4's

Rivarossi C&O H8 2-6-6-6 (#2 overhang offender)

 

Sheldon

    

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Posted by selector on Sunday, August 8, 2021 4:08 PM

I'll second Sheldon's Rivarossi H-8.  My 2005/6 version came with two cabs, believe it or not.  The one installed had the shorter cab roof overhang of the two, the extension reaching back to the tender. They're fragile, and I broke the optional cab's extension. Dunce  Had I installed it, it's side clearance intrusion into track spacing would have been quite serious in my estimation.  The nose of this beast is bad enough, and the engineer's injector overflow catches on stuff near the tracks, things like shrubs or lineside details.  Beware!

While I have your attention, look up!  What trips me with overhead clearances are pantographs, the chimneys on the odd caboose, crane booms....don't just look to side clearances.  That NMRA gauge is just a guide.

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Posted by richhotrain on Monday, August 9, 2021 4:38 PM

selector

That NMRA gauge is just a guide. 

Exactly.

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Posted by IDRick on Monday, August 9, 2021 4:47 PM

Okay, quick question.  Designing a switching layout. Two places will have parallel tracks on curves.  Thinking of 22 and 24-inch radius curves.  HO scale, 4 axle locomotives and max car size is 60 ft.  Good?

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Posted by 7j43k on Monday, August 9, 2021 5:47 PM

On tangent track, you'll have half an inch between two cars with two inch track centers.

On a 24" radius curve, a 60' car will overhang INWARDS by a quarter inch.  Overhanging of cars OUTWARD will be less, maybe an eighth of an inch.  Probably less.

So.  You should be able to pull it off.  With at least an eighth of an inch to spare.

I say it will work.

But.

If I'm wrong, who loses here?

I recommend you build a couple of test curves to confirm things.  

 

Ed

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Posted by richhotrain on Monday, August 9, 2021 6:01 PM

7j43k

I recommend you build a couple of test curves to confirm things.   

Exactly. That is the smart thing to do.

Rich

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Posted by IDRick on Monday, August 9, 2021 6:42 PM

Okay, will mock it up when have some benchwork up...  Thanks.

 

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Posted by Doughless on Monday, August 9, 2021 7:58 PM

Arguments over mathmatics?  That's an interesting engineering/physics discussion, Einstein.  And accounting for the forces created by models that have essentially no mass would be a challenging calculation.

I would assume that the input variables would determine proper spacing, such as intended equipment length and the need for finger space should you want to handle the cars.

Kinda like the lack of absolute sandards real railroads would have, since input variables like available flat real estate and clearence for vehicle/people movements might be desirable and vary from location to location.

In a nutshell, although situations vary, but no matter what the situation, clearence is clearence.  Clarence.

Were you guys ever part of that "toast" thread that was on the forum many years ago, or that thread about the theoretical problems different screws might have when twisting into benchwork?  I liked those too. 

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Posted by 7j43k on Monday, August 9, 2021 8:25 PM

Railroads have no absolute standards?

4' - 8 1/2"

And there are standards for tolerance on that dimension.

 

There are Plate standards.  And all Plates have a maximum width of 10' - 8".

 

There are clearance standards, by States, in this case.  Washington and Oregon come to mind.  Those standards are for ALL railroads in each state.  They are remarkably similar.

It's pretty hard to set up a rail system that can move a railcar to anywhere track goes in North America without some kind of standards.

 

Ed

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Posted by Doughless on Monday, August 9, 2021 8:40 PM

Goodness.  I was refering to the context of the topic, the possibility that yards may have closer track spacing depending upon the types of equipment occupy the yard or the need for a vehicle to be able to get from one end to the other, among various other possible inputs to an equation.

I wasn't referring to the absense of standards about anything anywhere.

You guys crack me up.

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Posted by 7j43k on Monday, August 9, 2021 10:35 PM

Douglas,

It would have been good if you had used those very words the first time.  They are well written and clear.  Unfortunately, your earlier attempt was not.  What with "mathmatics", "Einstein", "toast", it was a bit meandering.

You make a good point by bringing in prototype practice, and that it might vary.  I think this was discussed recently in another topic.  I think the main concern here is on the layout level, however:  Crashing trains and room for fingers and such.

I am glad we provide levity for you.  I am sure you provide levity for some of us, and I hope that pleases you, also.

 

Ed

 

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Posted by richhotrain on Monday, August 9, 2021 11:00 PM

7j43k

Douglas,

It would have been good if you had used those very words the first time.  They are well written and clear.  Unfortunately, your earlier attempt was not.  What with "mathmatics", "Einstein", "toast", it was a bit meandering.

I was surprised by the sarcastic nature of that post by Douglas. It was out of character for him.

Plus, he spelled clearance wrong, twice. LaughLaugh

Rich

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Posted by Doughless on Tuesday, August 10, 2021 5:55 AM

richhotrain

 

 
7j43k

Douglas,

It would have been good if you had used those very words the first time.  They are well written and clear.  Unfortunately, your earlier attempt was not.  What with "mathmatics", "Einstein", "toast", it was a bit meandering.

 

 

I was surprised by the sarcastic nature of that post by Douglas. It was out of character for him.

 

Plus, he spelled clearance wrong, twice. LaughLaugh

Rich

 

I guess I thought with the exception of the only serious posts that addressed the topic correctly.....you and Kevin basically saying that "it depends" , that the bulk of the thread was unserious, semi scarcastic banter. 

I thought that theoretical discussions about preplanning the precision needed to lay track similar to engineers building a 747 was actually a big joke...like the Toast thread and the five page discussion on torquing a screw into plywood years ago.

My apologies for misunderstanding if folks were being serious.

BTW, an NMRA gauge?  I've been in the hobby 40 years and built three layouts (yes, successfully) and I never could figure out what I would use it for. 

Still having fun, with no derailments, mysteriously uncoupling cars, or shorts occuring on Peco turnouts.

 

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Posted by richhotrain on Tuesday, August 10, 2021 6:04 AM

Not sure where Kevin fits in here. I was agreeing with Ed that the OP should test the track for clearance, and I made that same argument earlier in the thread, the very first reply in fact. I was being totally serious. I am a big believer in mathematics, but I also respect empirical evidence. When you are dealing with clearance on curves, test it.

Anyhow, all's well that ends well.

Rich

P.S. It looks like you edited your last reply after I posted mine. The reference to engineers building a 747 totally baffles me. Are you confusing this thread with some other thread?

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Posted by Doughless on Tuesday, August 10, 2021 6:35 AM

richhotrain

Not sure where Kevin fits in here. I was agreeing with Ed that the OP should test the track for clearance, and I made that same argument earlier in the thread, the very first reply in fact. I was being totally serious. I am a big believer in mathematics, but I also respect empirical evidence. When you are dealing with clearance on curves, test it.

Anyhow, all's well that ends well.

Rich

 

Kevin offered his advice based on experience.  I thought that the advice that was based upon arguing the possible mathmatical solutions in the planning stages were less than sincere about answering the OPs question and more about something else...what I'm not sure.

If you take your advice about testing various combinations, and go through several iterations, you could lay two pieces of track, have it work for 40 years, and never ever know what the exact spacing between centers was.  

The only reason you would have to measure it...at all in 40 years... is if you were going to lay another track in exactly the same yard where the exact same equipment would run...where no vehicles would be passing...where no maintenance shed would be located.  Change one variable, and the spacing required changes too.  And, you wouldn't even need to measure it if you simply eyeballed it and had enough space to work with to account for being 3/32nds off on a few tracks. 

I guess I get frustrated when answers are given that imply its "only the engeering way or the hiway" when it comes to layout building.

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Posted by richhotrain on Tuesday, August 10, 2021 6:44 AM

Well, here is my reply to the OP, verbatim, and it was the first reply to this thread.

It was a serious reply based upon my own experience.

After I posted that reply to the OP, my subsequent replies were in support of Crandell's and Ed's similar responses - - - test the trackwork to see if it creates clearance problems or not.

Rich

richhotrain

I don't have an absolute answer for you, but I can make some suggestions.

A minimum radius of 36" is great, especially on mainlines, but not really necessary for yards. What is more important on curves is the spacing between tracks, and 2" on center on curves is tight even though you are limiting your rolling stock to 40' and 50' freight cars. Spacing of 2 1/2" on center on curves is far better, at least in my experience.

Years ago, I got some good advice from my LHS guys about spacing of tracks on curves. They recommended that I buy a pair of 85' boxcars and test them on actual track to be sure. I wouldn't blindly rely on the advice of others unless they can say with certainty that 2" on center spacing for 36" radius tracks will work based upon their actual experience.

If this were my layout, I would use 2 1/2" spacing on curves and, since it is the yard, I would step down the radius on curved tracks to something like 32" radius. In fact, that is exactly what I did on my old layout where I installed a yard on a curve on my layout.

Hope this helps.

Rich 

 

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Posted by Doughless on Tuesday, August 10, 2021 7:12 AM

richhotrain

Well, here is my reply to the OP, verbatim, and it was the first reply to this thread.

It was a serious reply based upon my own experience.

After I posted that reply to the OP, my subsequent replies were in support of Crandell's and Ed's similar responses - - - test the trackwork to see if it creates clearance problems or not.

Rich

 

 
richhotrain

I don't have an absolute answer for you, but I can make some suggestions.

A minimum radius of 36" is great, especially on mainlines, but not really necessary for yards. What is more important on curves is the spacing between tracks, and 2" on center on curves is tight even though you are limiting your rolling stock to 40' and 50' freight cars. Spacing of 2 1/2" on center on curves is far better, at least in my experience.

Years ago, I got some good advice from my LHS guys about spacing of tracks on curves. They recommended that I buy a pair of 85' boxcars and test them on actual track to be sure. I wouldn't blindly rely on the advice of others unless they can say with certainty that 2" on center spacing for 36" radius tracks will work based upon their actual experience.

If this were my layout, I would use 2 1/2" spacing on curves and, since it is the yard, I would step down the radius on curved tracks to something like 32" radius. In fact, that is exactly what I did on my old layout where I installed a yard on a curve on my layout.

Hope this helps.

Rich 

 

 

 

 

I know.  That's what I was saying.  I thought your post was a serious answer.  Yes, there were a few more scattered in but a lot of it reads like that five page long thread about what SHOULD happen when you torque different screws into different grades of plywood based upon the different properties designed into the steel and plywood. 

That was a thread that made fun of itself for being overserious about a simple question.  At least that's the way I read it.

Maybe I'm different and have simply gotten lucky.  Common sense has always worked for me.  But common sense tells me that I should not use common sense to build an airplane.Big Smile

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Posted by 7j43k on Tuesday, August 10, 2021 9:25 AM

My mathematical responses are completely serious.

Mathematics can be quite useful in our field.  For example, if you have a room 12 feet wide and you want layout 4 feet wide on each side, I can tell you the aisle width without having to lay out and measure a real room.  Or even measuring off of a scale drawing.

My calculations were a slight step above that operation.

I suggested building a test setup because of the "trust but verify" concept.  Plus, with our models, there can be an amazing amount of slop in mechanical dimensions, especially in trackwork.

Also, the layout builder might find that, although the clearances are what I predicted; in real life, those clearances are still too small for his tastes (sorta how they must do airplane seating).

 

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Posted by SeeYou190 on Tuesday, August 10, 2021 10:16 AM

7j43k
I suggested building a test setup

I always suggest building a test piece first. This is always time well spent.

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Posted by Doughless on Tuesday, August 10, 2021 10:17 AM

Anybody care to guess what this track spacing would scale down to in terms of inches on center?  Keeping in mind that its likely designed for a fairly uniform type of car. (Hoping the watermark printing satisfies copyright requirements).

Coal Piled In Railroad Cars Stock Photo - Download Image Now - iStock

 

Or this?

N&W – Blogging the Railroad Tunnels

Or the yard that has access down the middle?

 9,029 Coal Rail Photos - Free & Royalty-Free Stock Photos from Dreamstime

 Hard to tell....

113 Coal - Model Railroad Ballast

 

 Do all the tracks in a yard even have the same center spacing?  

 

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Posted by 7j43k on Tuesday, August 10, 2021 10:27 AM

Lastspikemike

Here's a thought: if 2" track centres on tight radius curves can't work why does Atlas make sectional track in 22" and 24" radii?  I note the absence of 20" radius sectional curves but 15" and 18" are made.

Doesn't Kato make sectional curves in 2" increments? 

 

 

No.

 

 

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Posted by SeeYou190 on Tuesday, August 10, 2021 10:29 AM

Doughless
Anybody care to guess what this track spacing would scale down to in terms of inches on center? 

While traveling I remember seeing many signs that said something like No Room For Man In Between Train Cars in yards and industrial areas.

It looks like some of those places should have those signs.

Surprise

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Posted by 7j43k on Tuesday, August 10, 2021 10:38 AM

Doughless

Anybody care to guess what this track spacing would scale down to in terms of inches on center? 

Or the yard that has access down the middle?

 9,029 Coal Rail Photos - Free & Royalty-Free Stock Photos from Dreamstime

 

 

I'm not guessing.  I'm using that mathematics thing, again:

I can't tell the track spacing on the other two, but the one above is about 12' -6", or 1 3/4" in HO.  I guess they're not followers of Inch-and-a-half Mike.

 

The curves are clearly hugely wider than what we use, and I doubt there'd be a need to increase track centers if it were reproduced in HO.

 

If you're advocating such a spacing in HO, it does make sense if you don't feel the need to reach in and pick up or rerail a car.  

If I had the room, and I were building a staging yard, I would want 2 1/2" to 3", for easy finger clearance.  Most people, probably including me, would likely shrink that number for more tracks.  Remember, staging can include adding and removing cars.

 

I'll mention that, in the real world, I worked on a project that had a 3" clearance between train and (large) obstruction.  

 

Ed

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Posted by SeeYou190 on Tuesday, August 10, 2021 10:43 AM

Doughless
Do all the tracks in a yard even have the same center spacing?  

No.

I can tell you by actual physical measurement, the SEMINOLE GULF yard in Fort Myers, Florida has 4 tracks, and none of the track spacing is equal.

However, every track is perfetly straight. I like the curved yards much better. Mine will be built on a very broad arc.

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Posted by IDRick on Tuesday, August 10, 2021 11:14 AM

IDRick

Okay, will mock it up when have some benchwork up...  Thanks.

 

Since I am in the planning phase, I'm going to just go to a 2-1/2 inch track spacing throughout my HO switching layout.  My four axle diesels and 60 ft cars should not have any problems "interacting" with cars/locos on adjacent straight or curved track.  Much easier to plan with software using a common spacing and will fit easily on the planned benchwork.  Yard will only have five tracks and in the switching area, max of two through tracks plus sidings.

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Posted by Doughless on Tuesday, August 10, 2021 11:27 AM

7j43k

 

 
Doughless

Anybody care to guess what this track spacing would scale down to in terms of inches on center? 

Or the yard that has access down the middle?

 9,029 Coal Rail Photos - Free & Royalty-Free Stock Photos from Dreamstime

 

 

 

 

I'm not guessing.  I'm using that mathematics thing, again:

I can't tell the track spacing on the other two, but the one above is about 12' -6", or 1 3/4" in HO.  I guess they're not followers of Inch-and-a-half Mike.

 

The curves are clearly hugely wider than what we use, and I doubt there'd be a need to go smaller in HO.

 

If you're advocating such a spacing in HO, it does make sense if you don't feel the need to reach in and pick up or rerail a car.  

 

I'll mention that, in the real world, I worked on a project that had a 3" clearance between train and (large) obstruction.

 

Ed

 

Sorry, having implicit understanding of that math thing, I know that an answer is not mathematically precise once the inputs start with the word "about".  

Since the math thing only really finds a precise answer when all of the inputs are constant knowns, the only math that matters here is when you plug your guess into the formula that scales your guess down to an HO relevant guess.

Which is what I asked for.  Thanks.  BTW, I guessed the same 1.75 inches.

And I guessed it replicating the pics by using two pieces of track, two hopper cars, and not even a micrometer (thats a hobby tool?) but the little pink ruler my daughter used in 4th grade.     

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Posted by ATLANTIC CENTRAL on Tuesday, August 10, 2021 11:32 AM

Just to share related info in both threads........

I'm not going to argue, dispute, suggest or disagree with anything or anybody here. 

I'm just going to make three simple statements.

First, as orginally suggested by several/many so far, simple testing is always a good idea.

Second, the NMRA has always been very "generous", and thereby conservative in its recomendations for curved track centers. Yet they have always "danced around" the tangent track center issue with scale feet rather than a real life dimension.

Their 14 scale foot recommendation is 1.931"..........

Third, I have used 2" track centers for tangent track since I was introduced to this hobby. As explained earlier it is the defacto industry standard for bridges, crossovers, etc.

I have used 2" track centers on curves, maybe sometimes stretching them out to 2-1/8", ever since I started using 36" radius as my minimum.

I have tested this with locos as big as the Bachmann EM-1 passing 80' Bachmann and Branchline passenger cars with no issues and room to spare.

So for appearance, space and better track civil engineering (yes, I engineer the track location before I install it), I will stay with 2" (or cheat them up just that 1/8") track centers. The NMRA recommended 2-15/32" is just ugly and unnecessary at 36" radius and above.

DISCLAIMER - I don't own a UP BigBoy, brass plastic or diecast, and I have no plans to ever own one. So I think the EM-1 qualifies as a large enough test loco.

Sheldon 

    

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Posted by 7j43k on Tuesday, August 10, 2021 11:48 AM

ATLANTIC CENTRAL

 

DISCLAIMER - I don't own a UP BigBoy, brass plastic or diecast, and I have no plans to ever own one. So I think the EM-1 qualifies as a large enough test loco.

 

 

DISCLAIMER ON DISCLAIMER:

IF you might be running articulateds that don't swivel the "rear" engine, you do need to be careful about curve spacing where they run.

I mentioned the Big Boy earlier, that has a half inch overhang on a 37" curve.  And that's the theoretical (mathematics again at work, here).  YOUR model might be more.

But it's not just Big Boy's.  There are other big articulateds that come mighty close.

And, lest you think that the above comment only applies to those darn brass locos, I remind you that the Intermountain Cab Forward does not have a swivel "rear" engine.

Maybe someone will make another plastic non-swivel articulated someday.  Maybe.

 

 

Ed

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Posted by Doughless on Tuesday, August 10, 2021 12:10 PM

And, the NMRA standards are obviously smart guidelines from which to alter, if you want, based upon how you are going to run your layout.  If you are going to run it generically, that's fine, then calculating precision beyond the guidelines seems like a waste of time.

However, if you ask questions like...do I need to run 85 foot long cars an every yard track, or a big boy on every track?  If not, you can then cut down the spacing between tracks to something like my pics posted above...since it appears that CSX/NS will not be running 89 foot flat cars along side the coal hoppers.

Does spacing need to be the same for every track?  Obviously, the radius will be descending as you move inwards along a curved yard. 

So many variables, so few constants. 

 

 

- Douglas

MSM
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Posted by MSM on Tuesday, August 10, 2021 1:00 PM

[quote user="richhotrain"]

Well, here is my reply to the OP, verbatim, and it was the first reply to this thread.

It was a serious reply based upon my own experience.

After I posted that reply to the OP, my subsequent replies were in support of Crandell's and Ed's similar responses - - - test the trackwork to see if it creates clearance problems or not.

Rich

 

 
richhotrain

I don't have an absolute answer for you, but I can make some suggestions.

A minimum radius of 36" is great, especially on mainlines, but not really necessary for yards. What is more important on curves is the spacing between tracks, and 2" on center on curves is tight even though you are limiting your rolling stock to 40' and 50' freight cars. Spacing of 2 1/2" on center on curves is far better, at least in my experience.

Years ago, I got some good advice from my LHS guys about spacing of tracks on curves. They recommended that I buy a pair of 85' boxcars and test them on actual track to be sure. I wouldn't blindly rely on the advice of others unless they can say with certainty that 2" on center spacing for 36" radius tracks will work based upon their actual experience.

If this were my layout, I would use 2 1/2" spacing on curves and, since it is the yard, I would step down the radius on curved tracks to something like 32" radius. In fact, that is exactly what I did on my old layout where I installed a yard on a curve on my layout.

Hope this helps.

Rich 

 

 
Gentleman,
 
As I’ve been following this thread, I realized that my track plan was not only inaccurate, but that I jumped the gun in posting it, my bad.  I apologize not only for not participating in this thread (don’t have the knowledge) and by for not mentationing that I intend to run large articulated locomotives.

I did some trial and error as suggested with the equipment I have and incorporated a lot of the suggestions that were made.  With that being said, I made the following adjustments:

 ·        Main line radius minimum 42”

 ·        Yard radius minimum 36” except for car shop where I’m using  28” - 32” curved turnouts

 ·        Main line track spacing is 2 ½

 ·        Yard and arrival / depart tangent spacing is now 2 ¼

 ·        West end of the yard, arrival / departure tracks are now spaced 2 ½ with easements

 ·        Inner arrival / departure track was extended about 30” from end curve to turnout

 ·        Yard ladders and other select turnouts were rearranged to accommodate “Caboose” ground throws

Last concern I have is do I need to space my yard turns (Freight Yard - 5 Tracks) at 2 1/2 or would 2 1/4 work considering 40' - 65' freight car lengths?

If anyone happens to notice anything else that might be a concern, I’d appreciate a comment or so…

Thanks

MSM

 

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Posted by IDRick on Tuesday, August 10, 2021 1:10 PM

ATLANTIC CENTRAL

Third, I have used 2' track centers for tangent track since I was introduced to this hobby. As explained earlier it is the defacto industry standard for bridges, crossovers, etc.

I have used 2" track centers on curves, maybe sometimes stretching them out to 2-1/8", ever since I started using 36" radius as my minimum.

I have tested this with locos as big as the Bachmann EM-1 passing 80' Bachmann and Branchline passenger cars with no issues and room to spare.

So for appearance, space and better track civil engineering (yes, I engineer the track location before I install it), I will stay with 2" (or cheat them up just that 1/8") track centers. The NMRA recommended 2-15/32" is just ugly and unnecessary at 36" radius and above.

Sheldon 

 

 
Sheldon, what spacing would you recommend for two parallel tracks (HO) with a minimum radius of 24 inches?  While I like your standard of 36" or greater curves, l just can't fit them into my switching shelf layout...  4 axle diesels, 60 foot cars, 18" shelves
 
 
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Posted by ATLANTIC CENTRAL on Tuesday, August 10, 2021 2:05 PM

IDRick

 

 
ATLANTIC CENTRAL

Third, I have used 2' track centers for tangent track since I was introduced to this hobby. As explained earlier it is the defacto industry standard for bridges, crossovers, etc.

I have used 2" track centers on curves, maybe sometimes stretching them out to 2-1/8", ever since I started using 36" radius as my minimum.

I have tested this with locos as big as the Bachmann EM-1 passing 80' Bachmann and Branchline passenger cars with no issues and room to spare.

So for appearance, space and better track civil engineering (yes, I engineer the track location before I install it), I will stay with 2" (or cheat them up just that 1/8") track centers. The NMRA recommended 2-15/32" is just ugly and unnecessary at 36" radius and above.

Sheldon 

 

 

 
Sheldon, what spacing would you recommend for two parallel tracks (HO) with a minimum radius of 24 inches?  While I like your standard of 36" or greater curves, l just can't fit them into my switching shelf layout...  4 axle diesels, 60 foot cars, 18" shelves
 
 
 

As mentioned, testing is good. But 24" radius will likely require at least 2-3/8", possibly more. And that assumes the equipment choices you mentioned.

Sheldon

    

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Posted by Pruitt on Tuesday, August 10, 2021 2:06 PM

MSM
Gentleman,
 
As I’ve been following this thread, I realized that my track plan was not only inaccurate, but that I jumped the gun in posting it, my bad.  I apologize not only for not participating in this thread (don’t have the knowledge) and by for not mentationing that I intend to run large articulated locomotives.

I did some trial and error as suggested with the equipment I have and incorporated a lot of the suggestions that were made.  With that being said, I made the following adjustments:

 ·        Main line radius minimum 42”

 ·        Yard radius minimum 36” except for car shop where I’m using  28” - 32” curved turnouts

 ·        Main line track spacing is 2 ½

 ·        Yard and arrival / depart tangent spacing is now 2 ¼

 ·        West end of the yard, arrival / departure tracks are now spaced 2 ½ with easements

 ·        Inner arrival / departure track was extended about 30” from end curve to turnout

 ·        Yard ladders and other select turnouts were rearranged to accommodate “Caboose” ground throws

Last concern I have is do I need to space my yard turns (Freight Yard - 5 Tracks) at 2 1/2 or would 2 1/4 work considering 40' - 65' freight car lengths?

If anyone happens to notice anything else that might be a concern, I’d appreciate a comment or so…

Thanks

MSM

MSM,
 
Based on my experience with a 36 inch minimum radius, 2" centers work fine even with 80' cars, so your relatively conservative (pardon that word) 2 1/4 to 2 1/2 inch centers should work great. It will give you ample clearance between cars on adjacent tracks, and will also provide finger space whenever you need to reach in for some reason. 
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Posted by SeeYou190 on Tuesday, August 10, 2021 2:07 PM

IDRick
I'm going to just go to a 2-1/2 inch track spacing throughout my HO switching layout. 

I like 2 1/2 inch spacing. I can get my fingers in there.

That is something the prototype does not take into consideration.

IDRick
  While I like your standard of 36" or greater curves, l just can't fit them into my switching shelf layout..

I cannot fit them in either.

Doughless
not even a micrometer (thats a hobby tool?)

Yes it is. I have two in my hobby box, and eight more in the big tool box in the garage.

I strongly believe in always using the best tool for the job.

Lastspikemike
You were supposed to look this up.

Gee Ed, the hall monitor called you out for not doing your homework!

Huh?

-Kevin

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Posted by ATLANTIC CENTRAL on Tuesday, August 10, 2021 2:18 PM

One more random thought, as it applies to ME, For my modeling style.

I try to avoid handling equipment other than steady it from the top when manually uncoupling.

I'm not an "active fiddle yard" kind of guy, I don't store much excess rolling stock off the layout.

That's why the new layout is designed to store 1,000 freight cars and 150 passenger cars.

Picking them up randomly in a freight yard or staging yard is just not an issue for me.

The whole layout is designed around 2" track centers.

Sheldon

    

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Posted by SeeYou190 on Tuesday, August 10, 2021 2:21 PM

ATLANTIC CENTRAL
I try to avoid handling equipment

I made a decision to include a carfloat on the new layout, and it will be "fiddled" in between play sessions.

I think I will also install an interchange track to be fiddled as well.

I overbuilt the Fleet Of Nonsense in the past four years by about 40 freight cars, and I still have more to build.

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Posted by Doughless on Tuesday, August 10, 2021 2:31 PM

Lastspikemike

 

 
7j43k

 

 
Lastspikemike

Here's a thought: if 2" track centres on tight radius curves can't work why does Atlas make sectional track in 22" and 24" radii?  I note the absence of 20" radius sectional curves but 15" and 18" are made.

Doesn't Kato make sectional curves in 2" increments? 

 

 

 

 

No.

 

 

Ed

 

 

 

You were supposed to look this up.

Kato HO curved sectional track is made in 2 3/8" radius increments, somewhat wider (by 3/16") than the Mark V NMRA gauge size. 

If it works for Kato and for Atlas.....?

 

Mike, as you are learning in this hobby, manufacturers make products that are incomplete.  The product can do some things, but fails at other things.  When judged with the standard that each product should do what the other guy's does, they all fall short of being competent because they were designed to only do limited applications.

The Atlas sectional track was designed, mainly, to provide train set type of 4 x 8 layouts way back in the day.  Their trackplan book has many plans with 22 inch radius curves inside a 24.  But those train set plans would not work if the buyer was running 85 foot passenger cars (which Atlas doesn't make BTW, AFAIK).  Atlas doesn't disclose that part. 

Producers don't disclose in what situations their product fails. For one reason, the list would be way too long.

We have to figure it out for ourselves. 

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Posted by ATLANTIC CENTRAL on Tuesday, August 10, 2021 2:36 PM

7j43k

 

 
ATLANTIC CENTRAL

 

DISCLAIMER - I don't own a UP BigBoy, brass plastic or diecast, and I have no plans to ever own one. So I think the EM-1 qualifies as a large enough test loco.

 

 

 

 

DISCLAIMER ON DISCLAIMER:

IF you might be running articulateds that don't swivel the "rear" engine, you do need to be careful about curve spacing where they run.

I mentioned the Big Boy earlier, that has a half inch overhang on a 37" curve.  And that's the theoretical (mathematics again at work, here).  YOUR model might be more.

But it's not just Big Boy's.  There are other big articulateds that come mighty close.

And, lest you think that the above comment only applies to those darn brass locos, I remind you that the Intermountain Cab Forward does not have a swivel "rear" engine.

Maybe someone will make another plastic non-swivel articulated someday.  Maybe.

 

 

Ed

 

I understand and agree, but I like the double swivel articulated locos, as I said earlier, they make our large (but still compressed) curves look larger. 8 of my 11 articulated locos are x-6-6-x designs anyway.

And, I don't see a long list of additional articulated locos in my future, brass or plastic.

I actually limit the rigid wheelbase of steam that I purchase to 21 scale feet, so the are no 4-12-2's on my shopping list either, or even any 2-10-4's for that matter.

Largest rigid wheelbase locos I have, USRA light 2-10-2's with 57" drivers.

These standards were imposed for appearance and operational reliability at the chosen minimum radius.

Sheldon

    

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Posted by Doughless on Tuesday, August 10, 2021 2:36 PM

SeeYou190
Doughless not even a micrometer (thats a hobby tool?) Yes it is. I have two in my hobby box, and eight more in the big tool box in the garage. I strongly believe in always using the best tool for the job.

I don't disagree with using the best tool for the job. 

I'm asking what are the jobs in model railroading where you need that level of precision? 

Boring out a cylinder, I get.  Laying track, or placing a trackside building, I'm lost.

That's not a challenge to your methods, its just that the discussions on the forums seemingly involve an ever more level of precision that I've never considered. and I'm wondering what I've been missing or doing wrong all of these years. 

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Posted by selector on Tuesday, August 10, 2021 3:16 PM

IDRick

Okay, will mock it up when have some benchwork up...  Thanks.

 

 

At which, we all close our eyes, smile, and emit a resounding, "AAAaaaahhh...!", like Bill Shatner as the MC in the talent show in that movie when the main character looks wide-eyed and then hastily adds, "...and world peace."

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Posted by IDRick on Tuesday, August 10, 2021 3:26 PM

selector

 

 
IDRick

Okay, will mock it up when have some benchwork up...  Thanks.

 

At which, we all close our eyes, smile, and emit a resounding, "AAAaaaahhh...!", like Bill Shatner as the MC in the talent show in that movie when the main character looks wide-eyed and then hastily adds, "...and world peace."

 

? Very strange response...  whatever  Sometimes replies are helpful and others not so much...

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Posted by ATLANTIC CENTRAL on Tuesday, August 10, 2021 4:37 PM

Doughless

 

 
SeeYou190
Doughless not even a micrometer (thats a hobby tool?) Yes it is. I have two in my hobby box, and eight more in the big tool box in the garage. I strongly believe in always using the best tool for the job.

 

I don't disagree with using the best tool for the job. 

I'm asking what are the jobs in model railroading where you need that level of precision? 

Boring out a cylinder, I get.  Laying track, or placing a trackside building, I'm lost.

That's not a challenge to your methods, its just that the discussions on the forums seemingly involve an ever more level of precision that I've never considered. and I'm wondering what I've been missing or doing wrong all of these years. 

 

You are likely not doing anything wrong, but you may not be involved in some aspects of the hobby that others are. I use my micrometer a fair amount.

But I kit bash locomotives, measure axle lengths for proper replacement fit, build the occasional custom turnout, etc.

But I'm the same guy that layed my straight track with a 36" steel rule, then checked it with a lazer...... we use them to install kitchen cabinets, why not use them to lay track?

Sheldon

    

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Posted by 7j43k on Tuesday, August 10, 2021 4:52 PM

Doughless

But those train set plans would not work if the buyer was running 85 foot passenger cars (which Atlas doesn't make BTW, AFAIK). 

 

They sell the old Branchline cars.  The sleepers are all 85'.

 

Ed

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Posted by 7j43k on Tuesday, August 10, 2021 5:02 PM

Doughless
That's not a challenge to your methods, its just that the discussions on the forums seemingly involve an ever more level of precision that I've never considered. and I'm wondering what I've been missing or doing wrong all of these years. 
 

If you get satisfactory results with your methods, you are not doing anything wrong.

If you see discussions that involve more precision than you care about, so what?  That's what THEY want to discuss.  I don't see why it would bother you if they do.  Just move on to a different topic.

 

Ed

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Posted by Doughless on Tuesday, August 10, 2021 5:09 PM

ATLANTIC CENTRAL

 

 
Doughless

 

 
SeeYou190
Doughless not even a micrometer (thats a hobby tool?) Yes it is. I have two in my hobby box, and eight more in the big tool box in the garage. I strongly believe in always using the best tool for the job.

 

I don't disagree with using the best tool for the job. 

I'm asking what are the jobs in model railroading where you need that level of precision? 

Boring out a cylinder, I get.  Laying track, or placing a trackside building, I'm lost.

That's not a challenge to your methods, its just that the discussions on the forums seemingly involve an ever more level of precision that I've never considered. and I'm wondering what I've been missing or doing wrong all of these years. 

 

 

 

You are likely not doing anything wrong, but you may not be involved in some aspects of the hobby that others are. I use my micrometer a fair amount.

But I kit bash locomotives, measure axle lengths for proper replacement fit, build the occasional custom turnout, etc.

But I'm the same guy that layed my straight track with a 36" steel rule, then checked it with a lazer...... we use them to install kitchen cabinets, why not use them to lay track?

Sheldon

 

I no longer build models, which is where precision that's measured in fractions of inches comes mainly into play.  The guys who ran the CAD program at Athearn that eventually popped out a styrene boxcar and installed all of its specific details did all of that precise work for me, so to speak.  And before that, Irv Athearn molded his BB stuff just fine, with only a little weathering needed.

We can't build structures to scale, they'd be huge.  We can't lay curves to scale, they'd eat up the room.  I'm baffled by all of the conversations about fractions of inches and how it makes a difference in realism when we are challenged by so many other things we can't change. 

 

You've mentioned a few areas, but most here asking questions are not going to rebuild their trucks or build a custom turnouts.  

Threads wander.  It seems like lately they wander down the path of precision just for the sake of it.

- Douglas

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Posted by 7j43k on Tuesday, August 10, 2021 5:12 PM

Doughless

Sorry, having implicit understanding of that math thing, I know that an answer is not mathematically precise once the inputs start with the word "about".  

Since the math thing only really finds a precise answer when all of the inputs are constant knowns, the only math that matters here is when you plug your guess into the formula that scales your guess down to an HO relevant guess.

Which is what I asked for.  Thanks.  BTW, I guessed the same 1.75 inches.

And I guessed it replicating the pics by using two pieces of track, two hopper cars, and not even a micrometer (thats a hobby tool?) but the little pink ruler my daughter used in 4th grade.     

 

 

I certainly wasn't going after precision.  Oddly, mathematical tools work on both precise and imprecise dimensions.  

I know the typical width of a freight car is 1 1/2" (about) in HO.  So I simply scaled the width of the car and the width of the open space between the cars, set up a proportion, and solved for x (x being the HO distance between the cars).  Adding 1 1/2 and 1/4, I got my answer.

As I said, I wasn't guessing.  And neither did you, if you built a sufficiently accurate model to measure.

 

Ed

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Posted by 7j43k on Tuesday, August 10, 2021 5:15 PM

Doughless

Threads wander.  It seems like lately they wander down the path of precision just for the sake of it.

 

Other people's interest in precision seems to be really bothering you.  Again, if a topic is becoming of no interest to you, why not just drop it, and leave it for the people who DO have an interest?

 

Ed

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Posted by SeeYou190 on Tuesday, August 10, 2021 5:26 PM

Doughless
SeeYou190
Doughless not even a micrometer (thats a hobby tool?) Yes it is. I have two in my hobby box, and eight more in the big tool box in the garage. I strongly believe in always using the best tool for the job.

I don't disagree with using the best tool for the job. 

I'm asking what are the jobs in model railroading where you need that level of precision? 

Doug, sorry my intention was lost in the wording. I meant my response about using my professional set of precision micrometers in model building as a bit toungue-in-cheek.

In reality, for model building, all the precision I will ever need can be achieved with this 6" Mitutoyo dial caliper, and nothing more.

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Posted by Water Level Route on Tuesday, August 10, 2021 6:02 PM

Doughless

 

 
Lastspikemike

 

 
7j43k

 

 
Lastspikemike

Here's a thought: if 2" track centres on tight radius curves can't work why does Atlas make sectional track in 22" and 24" radii?  I note the absence of 20" radius sectional curves but 15" and 18" are made.

Doesn't Kato make sectional curves in 2" increments? 

 

 

 

 

No.

 

 

Ed

 

 

 

You were supposed to look this up.

Kato HO curved sectional track is made in 2 3/8" radius increments, somewhat wider (by 3/16") than the Mark V NMRA gauge size. 

If it works for Kato and for Atlas.....?

 

 

 

Mike, as you are learning in this hobby, manufacturers make products that are incomplete.  The product can do some things, but fails at other things.  When judged with the standard that each product should do what the other guy's does, they all fall short of being competent because they were designed to only do limited applications.

The Atlas sectional track was designed, mainly, to provide train set type of 4 x 8 layouts way back in the day.  Their trackplan book has many plans with 22 inch radius curves inside a 24.  But those train set plans would not work if the buyer was running 85 foot passenger cars (which Atlas doesn't make BTW, AFAIK).  Atlas doesn't disclose that part. 

Producers don't disclose in what situations their product fails. For one reason, the list would be way too long.

We have to figure it out for ourselves. 

 

I would take this a bit further to say that 22" radius sectional track is made as it makes a 180 curve that fits nicely on the 'ol 4x8 sheet of plywood.  24" radius seems to be a not uncommon minimum radius on manufactured equipment and was the old "standard" radius curve according to John Armstrong (among others, I'm sure).  Seems like logical reasons to offer them both.  Not necessarily that they are meant to be used next to each other.  For example, Atlas also makes a #8 turnout and a "snap-switch" that are not intended to be used together to build a crossover.  Yet there they both are for sale under the Atlas banner.  15" and 18" were old standards.  20" lacked enough reason to exist.

If it was so great why would Kato go a different route in our copycat hobby?

As for Atlas track plans showing tight curves paired up, I've not looked at an Atlas book in many moons, but I seem to recall seeing this before.  However, I also recall seeing that the center points of the curves were not the same.  The outer track didn't start curving until after the inner had started so they did not have a 2" spacing in the curve.  If their tangent centerlines were greater than 2" already, it would make this a necessity to still allow their sectional track to work in the plan.

Mike

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Posted by Doughless on Tuesday, August 10, 2021 7:10 PM

7j43k

 

 
Doughless

Threads wander.  It seems like lately they wander down the path of precision just for the sake of it.

 

 

 

Other people's interest in precision seems to be really bothering you.  Again, if a topic is becoming of no interest to you, why not just drop it, and leave it for the people who DO have an interest?

 

Ed

 

Because the topic isn't really about precision.  That's the topic after hijack. The topic was answered by suggesting live iterations should be how spacing is determined.  Whether or not OP even bothers to measure the precise distance beyond the eyeball distance the hands on iterations provided is rather inconsequential to the goal.

But I suppose measurements could provide a supporting role, so he doesn't have to perform an iteration for each track.....provided of course that the radius doesn't change as he moves inward...DOH!

 Maybe he could just add about an 1/8 of an inch to each center line as he moves inward, determined by your pink plastic ruler of course, and call it problem solved.

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Posted by Doughless on Tuesday, August 10, 2021 7:30 PM

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As for Atlas track plans showing tight curves paired up, I've not looked at an Atlas book in many moons, but I seem to recall seeing this before.  However, I also recall seeing that the center points of the curves were not the same.  The outer track didn't start curving until after the inner had started so they did not have a 2" spacing in the curve.  If their tangent centerlines were greater than 2" already, it would make this a necessity to still allow their sectional track to work in the plan.

Yes, that is correct.  I do recall that several of their plans look like a electric race car track with lanes rather than a model railroad.  Perfectly concentric half circles fitting inside one another with the start of the curves way back on the straights.  The only way those curves could be made is with sectional track...and I don't know that all plans fit on a 4 x 8, so they could have used 24 and 22, but that's just an assumption at this point.

Still, I would say that thoseplans would work with shorter cars, but thinking they could be run with longer cars that Atlas did not make might be disappointing to the planner.  

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Posted by Doughless on Tuesday, August 10, 2021 7:46 PM

7j43k

 

 
Doughless

Sorry, having implicit understanding of that math thing, I know that an answer is not mathematically precise once the inputs start with the word "about".  

Since the math thing only really finds a precise answer when all of the inputs are constant knowns, the only math that matters here is when you plug your guess into the formula that scales your guess down to an HO relevant guess.

Which is what I asked for.  Thanks.  BTW, I guessed the same 1.75 inches.

And I guessed it replicating the pics by using two pieces of track, two hopper cars, and not even a micrometer (thats a hobby tool?) but the little pink ruler my daughter used in 4th grade.     

 

 

 

 

I certainly wasn't going after precision.  Oddly, mathematical tools work on both precise and imprecise dimensions.  

I know the typical width of a freight car is 1 1/2" (about) in HO.  So I simply scaled the width of the car and the width of the open space between the cars, set up a proportion, and solved for x (x being the HO distance between the cars).  Adding 1 1/2 and 1/4, I got my answer.

As I said, I wasn't guessing.  And neither did you, if you built a sufficiently accurate model to measure.

 

Ed

 

7j43k

 

 
Doughless

Sorry, having implicit understanding of that math thing, I know that an answer is not mathematically precise once the inputs start with the word "about".  

Since the math thing only really finds a precise answer when all of the inputs are constant knowns, the only math that matters here is when you plug your guess into the formula that scales your guess down to an HO relevant guess.

Which is what I asked for.  Thanks.  BTW, I guessed the same 1.75 inches.

And I guessed it replicating the pics by using two pieces of track, two hopper cars, and not even a micrometer (thats a hobby tool?) but the little pink ruler my daughter used in 4th grade.     

 

 

 

 

I certainly wasn't going after precision.  Oddly, mathematical tools work on both precise and imprecise dimensions.  

I know the typical width of a freight car is 1 1/2" (about) in HO.  So I simply scaled the width of the car and the width of the open space between the cars, set up a proportion, and solved for x (x being the HO distance between the cars).  Adding 1 1/2 and 1/4, I got my answer.

As I said, I wasn't guessing.  And neither did you, if you built a sufficiently accurate model to measure.

 

Ed

 

I guessed.

I only set up the model because I don't naturally know what 2 inch center spacing looks like between rail cars.  That's measuring, not math.

When I did,  and had it as a memory point of reference, I got the the 1.75 inch spacing 2 seconds after looking at the picture by guessing. 

Not sure why wasting my time using math would have been better or more precise as it hardly ever is worth the time in this capacity.

Not even knowing the width of a real rail car, (what is it 10.6 or 11.6) or the width of a model (whats that scale down formula again), even minimally hindered my arrival at the correct answer.

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Posted by 7j43k on Tuesday, August 10, 2021 7:50 PM

Doughless

Because the topic isn't really about precision.  That's the topic after hijack. The topic was answered by suggesting live iterations should be how spacing is determined.  Whether or not OP even bothers to measure the precise distance beyond the eyeball distance the hands on iterations provided is rather inconsequential to the goal.

But I suppose measurements could provide a supporting role, so he doesn't have to perform an iteration for each track.....provided of course that the radius doesn't change as he moves inward...DOH!

 Maybe he could just add about an 1/8 of an inch to each center line as he moves inward, determined by your pink plastic ruler of course, and call it problem solved.

 

 

You are starting to splutter.  I suggest you take some time to calm down.

 

Ed

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Posted by Track fiddler on Tuesday, August 10, 2021 8:14 PM

Good call Ed

A bit more of a chance to see things realistically.

My experience of spacing in yards or anything else you need a little spacing of your fingers to get through while you're fumbling around with your fingers to separate trains.

Realistically HO provides more of that.  N sale provides a bit more of a challenge!

 

I would like to say it's good to see you here again Ed.

I was sad when you went away for a whileIndifferentWink

 

 

 

TF

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Posted by 7j43k on Tuesday, August 10, 2021 8:25 PM

Thanks, TF.

The place changed for the better, so I came back.

I do think it is interesting to consider whether or not one needs "finger room".  And how much.

IF you can keep your trains on the track (and I know it CAN be done), and IF you don't need the track to add or remove rolling stock, I can see having narrow track spacing--something I hadn't given much thought to until this topic.  My WAG on spacing here would be 1 3/4".  You could pick up one more track after doing 7.  Or is it 8?

On t'other hand.  If you can't and/or do (see above), then wider spacing is necessary.  Measuring my finger with my trusty plastic pink ruler, I get about 5/8". So I guess, in this case, I'd be interested in a bit over 2", say 2 1/4". 

 

All that's leaving out the curves, of course.  And the brass articulateds--those lovely creatures!!!

 

 

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Posted by Track fiddler on Tuesday, August 10, 2021 8:45 PM

LaughLaugh

I know Ed,

I think it's kind of like the spock thing

If you keep your two fingers on the top of the cars,  uncoupling them with the barbecue skerew.  You might be okay separating them with N as I do.

LaughLaughLaugh

If you're lucky as me without derailing them that is!

 

 

 

TF

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Posted by Doughless on Wednesday, August 11, 2021 9:58 AM

Lastspikemike

Looking at an old Atlas track catalogue they do indeed start and end the broader curves about a 1/4 straight past the end of the tangent of the inner radius track, and add that same 1/4 track at the apex of the outer curve. Using 18" inner and 22" outer radius. But only for HO. For N track plans they run the two curves exactly in parallel, constant spacing.

Looking at Armstrong's book he acknowledges that prototype track spacing scales down to 1 3/4". (13'). He suggests 2 1/8" is enough for 30" radius and progressively wider for tighter curves. He suggests 2" for tangent tracks claiming that it makes our overscale rails look more real. He assumes Code 100 rail I believe. The prototype 13' doesn't work on our model curves because our model curves aren't to proper scale. We should use the minimum spacing we can get away with because it will always look too wide anyway.

He remarks that yard tracks should be wider spaced to allow for fingers. I say don't plan on using your fingers.

I suggest all this is not necessary and that 2" works for most layouts on mainlines and for curved yard tracks. Then 1 3/4" (or so) works for tangent yard tracks. 

You could use 1 1/2" for tangent yard tracks without cars hitting each other. But why would you. Woodland Scenics trackbed is 1 3/4" wide and that provides a useful minimum spacing.

 

The issue is that as you build multiple yard tracks on a curve, the radius of each ensuing track (as you move inward) gets tighter.  So the spacing that works for one pair of tracks won't work for the next adjacent track.  (Remember the overhang discussion)

It seems that you have to continually increase the spacing as the radius gets tighter, eating up valuable benchwork. (My rough guess was a 1/8th inch increase in spacing for each track as you progress.)

This is a problem the prototype doesnt have generally because of their broad curves.  So our curved yards might look wonky compared to pics of the real thing.

OP could forbid certain length equipment from traversing the inner most tracks, thereby keeping the other tracks closer together to better replicate the pics I posted above.

Or do what I would do, use a 42 inch minimum radius everywhere and don't bother with any of this. Big Smile

BTW, I'll be blunt. 1.5" spacing looks stupid.

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Posted by ATLANTIC CENTRAL on Wednesday, August 11, 2021 10:24 AM

So my new layout will have not one, but two curves in the 25' long six/seven track freight yard. But the smallest radius will be 36", making the largest one 48". 2" centers will be fine......

Sheldon

    

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Posted by SeeYou190 on Wednesday, August 11, 2021 12:53 PM

My yard will only be four tracks, and I believe the curve on the tightest track will be about 72 inches. It is just for looks.

The reason I want such a broad curve is more a concern for coupler alignment when operating than side clearance. The tracks will be spaced at 2.5"

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Posted by richhotrain on Wednesday, August 11, 2021 2:11 PM

Doughless

The issue is that as you build multiple yard tracks on a curve, the radius of each ensuing track (as you move inward) gets tighter.  So the spacing that works for one pair of tracks won't work for the next adjacent track. 

Why does that not surprise me? Thanks for confirming that reality.

Rich

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Posted by SeeYou190 on Wednesday, August 11, 2021 2:53 PM

Track fiddler
If you're lucky as me without derailing them that is!

I don't have a problem with freight cars derailing in yards. 

I think this is highly unlikely since operation is so slow in these areas.

I do need to develop proficiency with the skewer.

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Posted by trainnut1250 on Wednesday, August 11, 2021 5:59 PM

To the OP:

While I am not a big fan of the overall design due to the reasons Dave H pointed out in the other thread, I do think that all the hand wringing and mis-information about track spacing is a bit over the top, but that is just me.

Testing: The spacing on the curves will likely be fine at 2” given how broad they are, but as others have stated, testing is key. I don’t like creating areas on the layout where certain cars and equipment can’t operate – especially in a yard - so I would test with the longest equipment with the most overhang. As others have stated if you are going to run big articulated steam or long passenger cars, thoroughly check clearances with this rolling stock in all directions.

Regarding fixed wheel base articulated steam: I have found that most of the modern plastic articulated steam has double swiveling driver sets (notable exception is the IM Cab Forward). Brass is another story – most of my brass articulateds use the same design as the prototype (fixed rear driver set) – increasing the radius necessary and the overhang….If you plan to run big brass, consider a little extra wiggle room in the curve spacing.

Regarding straight track spacing: Anything closer than 2” makes the yard look like a “parking lot of track” to my eye. Everyone has different aesthetics when it comes to how things look, but I ended up removing track from my yard to keep the rustic feel I was looking for. My thought processes in designing my yard are here:

http://thewilloughbyline.com/willoughby%20text/Willoughby%20Yard%20design.doc.pdf

Any design this complex will have to be laid out and thoroughly tested/vetted before it is made permanent. Don’t be afraid to make some changes as you go…

My two cents,

Guy

 

 

 

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Posted by SeeYou190 on Wednesday, August 11, 2021 6:43 PM

trainnut1250
I do think that all the hand wringing and mis-information about track spacing is a bit over the top, but that is just me.

Yes, the OP got $1,000,000.00 worth of nonsense in response to a simple two bit question.

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Posted by mikeGTW on Monday, August 16, 2021 10:05 AM
As for anyone saying 1.5" track spacing Not if you have a wide vision caboose
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Posted by 7j43k on Monday, August 16, 2021 10:17 AM

Thanks for the illustrative photo.

 

Maximum width for railroad cars in normal interchange is 10' - 8" (taken from various Plate diagrams in use).

 

10' - 8" = 128"

128" / 87.1 = 1.470"

 

1.5" - 1.470" = .030" (approximately 1/32")

 

A caboose is not in normal interchange service.

 

 

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Posted by Overmod on Monday, August 16, 2021 11:45 AM

mikeGTW
Not if you have a wide vision caboose...

What if you had two?  Whistling

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Posted by 7j43k on Monday, August 16, 2021 2:04 PM

Well, yeah Mike.

You already said that you had to scrap the most excellent 1 1/2" spaced yard when "we" moved.

 

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Posted by 7j43k on Monday, August 16, 2021 2:16 PM

Lastspikemike

Straight yard tracks can be down to 1.5" easily. 

7j43k

Hey, Mike.

Still waiting for your working example of 1.5" track spacing.

 

Ed

 

We had to take it apart to move the layout. Sorry, a never to be repeated situation.

 

 

Ed

 

 

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Posted by mikeGTW on Monday, August 16, 2021 3:12 PM

7j43k
Lastspikemike Straight yard tracks can be down to 1.5" easily.  7j43k Hey, Mike. Still waiting for your working example of 1.5" track spacing.   Ed

 

Ed I have four different wide vision caboose's  so that 1.5" or even the 1 3/4" is not good for me  

Besides I use #6 atlas swiiches and they are 2"  on center for ladder tracks

Sometimes I wonder does someone even have anything to photograph maybe that's why no posting of pictures

 

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Posted by 7j43k on Monday, August 16, 2021 3:45 PM

mikeGTW

 

 
7j43k
Lastspikemike Straight yard tracks can be down to 1.5" easily.  7j43k Hey, Mike. Still waiting for your working example of 1.5" track spacing.   Ed

 

 

Ed I have four different wide vision caboose's  so that 1.5" or even the 1 3/4" is not good for me  

Mike 1 1/2 will probably tell you to pull your cabooses off in your arrival/departure tracks, and you won't have any trouble in the yard itself.

Besides I use #6 atlas swiiches and they are 2"  on center for ladder tracks

Rail nippers and files can shrink that distance right down.  Should you care to.

Sometimes I wonder does someone even have anything to photograph maybe that's why no posting of pictures

It's a LOT of work, unless you're set up to do it regularly.  In my opinion.  Still, I'm inching (millimetering?) towards it.  I've got a nice Flikr account somewhere that I paid real money for.  Someday......

Or.  I could just play with my trains, instead.  And yack with my n'er-do-well pals online.

 

Ed

 

 

 

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Posted by maxman on Tuesday, August 17, 2021 3:16 PM

I don't know if this was mentioned above or not.  However, I was looking at the literature for the MicroEngineering Ladder Track System and they say that their system results in a "minimum track spacing of 2-1/16 inch (the NMRA standard) between body tracks".

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Posted by Doughless on Tuesday, August 17, 2021 3:58 PM

maxman

I don't know if this was mentioned above or not.  However, I was looking at the literature for the MicroEngineering Ladder Track System and they say that their system results in a "minimum track spacing of 2-1/16 inch (the NMRA standard) between body tracks".

 

Well, they've got the word ENGINEERING right in their name, so they have to pretend that the 1/16th inch matters. Big Smile

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Posted by ATLANTIC CENTRAL on Tuesday, August 17, 2021 5:07 PM

maxman

I don't know if this was mentioned above or not.  However, I was looking at the literature for the MicroEngineering Ladder Track System and they say that their system results in a "minimum track spacing of 2-1/16 inch (the NMRA standard) between body tracks".

 

Well, I'm not trying to make this thread any more crazy than it already is, but I did mention the NMRA Recommended Practice for tangent track a while back, and it is not 2-1/16".

First, the NMRA no longer has track centers as a "Standard" but rather as a "Recommended Practice". A trip to their web site will help explain that difference.

RP 7.1 says that the recommended track centers for tangent track can/should be based on prototype dimensions based on era.

MODELING ERA                PERIOD            CENTERS

Old-Time/Narrow Gauge    Before 1920      12 feet

Classic                               1920 to 1969     13 feet

Early Modern                     1969 to 1983     14 feet

Modern                               After 1983         14 feet

 

If we just go with the 14 foot number, that translates to 1.931", or, a bit under 1-15/16".

2" track centers are 14'-6"

2-1/16" track centers are just under 15'

The ME yard ladder is an interesting product, but not one I'm interested in. It uses #5 turnouts, it stacks them in very tight and adds a curve after the frog. This is common on ther prototype, but they are using larger turnouts.....

I have built yards with Atlas #4 Custom Line turnouts (which are really #4.5), but will never do that again, at least not on a steam era layout.

So I have little confidence that a yard built with #5's, and with a sharper ladder angle, would be satisfactory for my needs. 

Still happy to be using Atlas Custom Line designed completely around 2" track centers, making 2" track center yard ladders, and 2" crossovers with no cutting or filling, and who's #6 is the most gentle curve #6 on the market.

Sheldon

    

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Posted by maxman on Tuesday, August 17, 2021 9:34 PM

An innocent comment based on an observation and more froth gets spewed.

gg.  you guys need to get a life.

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Posted by Colorado Ray on Tuesday, August 17, 2021 9:35 PM

One thing to consider is different spacing for the receiving and departure yards from the classification tracks.  Modern practice would use 20 ft spacing for the R/D tracks to provide a safe environment for car inspectors.

if you want more information than you'll ever need on yard design, check out the FRA Yard Design Manual.

https://rosap.ntl.bts.gov/view/dot/32572/dot_32572_DS1.pdf?

Ray

 

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Posted by ATLANTIC CENTRAL on Wednesday, August 18, 2021 5:56 AM

maxman

An innocent comment based on an observation and more froth gets spewed.

gg.  you guys need to get a life.

 

It is interesting how "facts" are so bothersome to some people.........

Just another reason I spend way less time here.

Sheldon

    

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Posted by Overmod on Wednesday, August 18, 2021 6:28 AM

Colorado Ray
if you want more information than you'll ever need on yard design, check out the FRA Yard Design Manual. https://rosap.ntl.bts.gov/view/dot/32572/dot_32572_DS1.pdf?

 Be sure to read and comprehend Chapter 2 first.  

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Posted by maxman on Wednesday, August 18, 2021 9:08 AM

ATLANTIC CENTRAL

 

 
maxman

An innocent comment based on an observation and more froth gets spewed.

gg.  you guys need to get a life.

 

 

 

It is interesting how "facts" are so bothersome to some people.........

Just another reason I spend way less time here.

Sheldon

 

Facts?  Facts?  What "facts"?  I said nothing that required a "fact" check.  I only passed along someone else's statement.  Sorry that you find that bothersome.

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Posted by Doughless on Wednesday, August 18, 2021 9:28 AM

Lastspikemike
One puzzle is how the yard ladder system can yield more siding length in the same space while using the 2"+ track centres. That seems impossible geometrically.

I have not seen the system so I am speaking from what I read about it.  I think the goal is to make the ladder track more upright rather than stretched out to save length, which one of the main problems with yards and model railroads.  I think they stack them together to keep the geometry of the closure and diverging tracks as gentle as possible while still saving length. 

And just a guess:  The result is a ladder that has as much linear length as a ladder built with a traditional #4 frogged ladder, but able to use a #5.

I'll let you figure out if that's the case and how effective that is.

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Posted by 7j43k on Wednesday, August 18, 2021 11:49 AM

By rotating the spine of the stack of switches more to the vertical (compared to the incoming yard lead), the tracks at the "top" of the yard can be a bit longer.  There has to be a slight curve to bring the diverging tracks back to parallel with the yard lead.

The spacing of the switches in the stack has to lessen, too (along the length of the stack); so that you can maintain your track spacing (which otherwise spreads out a bit).

This clever trick ends when you have shoved the stack of switches together enough so that the points of one are just after the frog of another.

 

ME does it with special switches.  It would work with regular ones, too.  Maybe not as well/smoothly, though.

 

Here's an example using Atlas Customline #6's:

 

For the straight part of the switch, there are 4 ties beyond the points, and 12 ties beyond the frog.  Let's remove all but two at each location.  The switch is now 71% as long as a stock switch.

Recall that it's been said that the stock switch gives you 2" yard track spacing.  If that's the case, a ladder built of the modified switches would give you a spacing of 1.42".  

Assuming you want to stick with the 2" spacing, you could regain that by putting a bit of curved track in, after the frog, on the diverging track.  Yes, I can prove it.

This brings the yard tracks "down" at an angle.  If you rotate the spine of switches (and the associated yard tracks) into a more "vertical" position, the yard tracks can again be parallel to the yard lead.

And in doing this, you get progressively longer yard tracks as you go "up".

 

 

Ed

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Posted by cuyama on Wednesday, August 18, 2021 12:19 PM

--
One puzzle is how the yard ladder system can yield more siding length in the same space while using the 2"+ track centres.

As others have said, this is a well-established idea. Adding a slight curve to the diverging leg of the first turnout increases the angle a bit, increasing (slightly) the length of the body tracks. One can do this with any turnouts, the ME system just includes the curves as part of the pre-fab turnouts. In the example below, the added curves are in red.

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Posted by 7j43k on Wednesday, August 18, 2021 2:39 PM

cuyama

 

 

Why the change from the Walthers #6 to the "NMRA" #6?

My guess would be that the "NMRA" are shorter, so as to maintain the 2" spacing.

It looks like, very roughly, one picks up 11" more yard capacity with the lower design--a nominal two cars.

 

Ed

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Posted by Doughless on Wednesday, August 18, 2021 3:19 PM

Lastspikemike
It's how you also shorten the whole ladder without also narrowing the track centres closer together.

If you look at real railroads, in tight spaces they try to put the points of the next turnout as close to the closure rail of the previous turnout as possible.

Our model track components can't do that, they need lots of track in between to maintain structure, but ME tries to as much as is feasible by making some of the components as stumpy as possible.

If you could stack the points one after the other, you could have broader radius closure rails (and the same radius beyond the frog) and an upright ladder that doesn't take up a lot of linear inches.  Those are the real goals here, broad radius with little length.

As long as the closure rail radius is broad enough (as well as the embedded radius of the whole shmear including point rails), what the resulting frog number happens to be is tertiary.

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Posted by cuyama on Wednesday, August 18, 2021 3:22 PM

7j43k
Why the change from the Walthers #6 to the "NMRA" #6? My guess would be that the "NMRA" are shorter, so as to maintain the 2" spacing.

I made the graphic a long time ago, so I don't remember why. But you're right, apples-to-apples would have been better – and one would probably need to trim the Walthers to use them with curves as shown with 2" spacing. But since folks (OK, one folk) expressed confusion about how it worked, I just posted what I had on-line already.

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Posted by 7j43k on Wednesday, August 18, 2021 4:49 PM

cuyama

I made the graphic a long time ago, so I don't remember why. But you're right, apples-to-apples would have been better – and one would probably need to trim the Walthers to use them with curves as shown with 2" spacing. 

 

It's a terrific graphic, and I'm glad you posted it.  It does give a very good sense of how it works.

I did a bit of calculating, and came up with shortening the Walthers switch by about 2.1" to keep the 2" spacing.  There's about 3.6" available for removal in the Walthers turnout, so should be no problem.

 

Ed

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Posted by riogrande5761 on Wednesday, August 18, 2021 5:22 PM

One of the things I like about Peco turnouts is they are already very short, the likihood of needing to trim them is much lower.  But I've trimmed Atlas and other turnouts as needed to get them to fit.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by Overmod on Wednesday, August 18, 2021 5:32 PM

I seem to have missed this, but what's then length, nominal radius, and 'source' of the little pieces of curve inserted to make the trick work?

is there a source for making up a template or gauge to form this curve in flextrack connected to each 'shortened' switch, which might make this simple ? 

 

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Posted by cuyama on Wednesday, August 18, 2021 5:39 PM

Overmod
I seem to have missed this, but what's then length, nominal radius, and 'source' of the little pieces of curve inserted to make the trick work? is there a source for making up a template or gauge to form this curve in flextrack connected to each 'shortened' switch, which might make this simple ? 

In the past I have just made it with flextrack in N scale, it would also work for other scales. I use the minimum radius I have chosen for the yard (which might be different from the rest of layout). How much curve depends on the length and frog number of the turnouts that you choose as well as track spacing of the yard tracks – to me it’s a little bit of trial-and-error.

About 2-3 degrees of curvature added to the diverging leg of the first turnout has often worked well for me in designs for others – and then the corresponding curve on each yard track.

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Posted by richhotrain on Wednesday, August 18, 2021 5:49 PM

riogrande5761

One of the things I like about Peco turnouts is they are already very short, the likihood of needing to trim them is much lower.  But I've trimmed Atlas and other turnouts as needed to get them to fit. 

That is a distinct advantage of Peco over Atlas for a turnout - - 3". Peco is 9" in length whereas Atlas is 12" in length for a Code 83 #6 turnout. That can be crucial when space is at a premium.

Rich

Alton Junction

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Posted by 7j43k on Wednesday, August 18, 2021 6:29 PM

Overmod

is there a source for making up a template or gauge to form this curve in flextrack connected to each 'shortened' switch, which might make this simple ? 

 

 

 

Comes in an assortment of radii and lengths.

 

Ed

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Posted by Overmod on Wednesday, August 18, 2021 6:46 PM

7j43k
Comes in an assortment of radii and lengths.

Ed, those are worthless for the short curves and their transitions that are being described here.  Does the company make a special short 'transition' gauge for these ladders?  They should...
I'm well aware of the theory; I just saw it taught again.  I'm also aware of the theory of the coaxial escapement.  In order to actually build either, it is helpful to have methods and dimensions, not advice to kinda-sorta curve stuff to fit and live with any glitches.

I suspect cuyama could produce a template comparable to the transition spiral in MR that could be printed off, cut in thin sheet or whatever, and used to set this track by track.

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Posted by 7j43k on Wednesday, August 18, 2021 6:55 PM

Overmod

 

 
7j43k
Comes in an assortment of radii and lengths.

 

Ed, those are worthless for the short curves and their transitions that are being described here.  

 

 

And that is because........

 

Ed

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Posted by Overmod on Wednesday, August 18, 2021 7:00 PM

7j43k
And that is because........

1) They are too long; 2) they can't be subdivided to shorter segments; 3) they lack any transition from a 'regular' switch into the small curve segment; and 4) they likewise lack any transition from the short curve back to tangent.

A gauge facilitating laying the small curves involved here would have to fulfill all four of these, whereas the ones pictured can't do any.

(If there's anyone who knows where to find a single gauge that does what's needed, I'd expect one of the Eds would be the one to know...)

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Posted by cuyama on Wednesday, August 18, 2021 7:31 PM

Overmod
I suspect cuyama could produce a template comparable to the transition spiral in MR that could be printed off, cut in thin sheet or whatever, and used to set this track by track.

One could do this for one specific combination of turnouts, radius, etc., but it's not something that is one-size-fits-all. 

Of course, if one chooses not to go to the trouble of laying this out with flex, one could forgo the small increase in yard body track length and just use the stock turnout angles.

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Posted by Overmod on Wednesday, August 18, 2021 7:36 PM

cuyama
One could do this for one specific combination of turnouts, radius, etc., but it's not something that is one-size-fits-all. 

Yes, and the current situation (involving the stock #6s rotated to a steeper angle but preserving a given track spacing) can be used as the example.

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Posted by 7j43k on Wednesday, August 18, 2021 8:20 PM

Overmod

 

 
7j43k
And that is because........

 

1) They are too long;

They are aluminum, and can be cut to length in under a minute.  Filing the edges of the cut smooth might take weeks, of course.

2) they can't be subdivided to shorter segments;

See above.

3) they lack any transition from a 'regular' switch into the small curve segment; and 4) they likewise lack any transition from the short curve back to tangent.

Because these curves are so short, there is no room to have an easement (transition).  In addition, it would be wise to use a fairly wide radius curve, so as to lessen the stress on backing movements through the switches.  And this also lessens both the need for and the possibility to make an easement (transition).

The real problem with putting in these micro segments of curved track is to not have a kink at either end.  To that end, it would be wise to solder a length of flex to the diverging track, and bend it to shape in place.  That should eliminate the kinking possibility.

 

A gauge facilitating laying the small curves involved here would have to fulfill all four of these, whereas the ones pictured can't do any. 

 

Done.

 

Ed

 

 

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