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Yard Track Spacing and Radius...

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

Water Level Route
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.  

- Douglas

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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.

- Douglas

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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!!!

 

 

Ed

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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.

- Douglas

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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"

-Kevin

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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

Alton Junction

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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.

-Kevin

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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

 

 

 

see stuff at: the Willoughby Line Site

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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.

-Kevin

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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.

 

 

Ed

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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.

 

Ed

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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

- Douglas

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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.

- Douglas

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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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