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Yard Track Spacing and Radius...

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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..........

Sheldon  

    

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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

Alton Junction

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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 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

Living the dream.

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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 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 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 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 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 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 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 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 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 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 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 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

Alton Junction

MSM
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Yard Track Spacing and Radius...
Posted by MSM on Friday, August 6, 2021 1:19 AM

First of all, I’d like to thank everyone who has contributed to my two posts. 

The knowledge I have gained is amazing and all the contributions has made it possible to make some needed adjustments, corrections, and a few additions.

With that being said, I have decided to extend my East side arrival, departure, and freight yard for operational purposes.  Due to my limited space the East end of my yard is now curved which brings me to my main concern. 

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 (diagram attached).

Thanks in advance…

MSM

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