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Double track in curve

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  • Member since
    June 2019
  • 24 posts
Double track in curve
Posted by MikeN8FWD on Wednesday, March 16, 2022 3:29 PM

Hello,

I am using a double track with a 42inch curve and was going to use a 40 inch , after reading I should use 2 inch or 3 inch center to center. I am going to run Walthers B&O 85 foot passenger cars. I was curious would the 3 inch spacing look silly?
Thanks,

Big Mike

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Posted by ndbprr on Wednesday, March 16, 2022 3:35 PM

Depends how big the difference is but real railroads did the same thing.  I don't think you will have any problems on that size radius. You can check with a couple cars on a test curve.  You shouldn't have to do much.  Maybe less then a 1/8" difference in the radii.  The worst case is the end of a car passing the center of the other car.  That is where they are closest.

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Posted by richhotrain on Wednesday, March 16, 2022 4:20 PM

MikeN8FWD

Hello,

I am using a double track with a 42inch curve and was going to use a 40 inch , after reading I should use 2 inch or 3 inch center to center. I am going to run Walthers B&O 85 foot passenger cars. I was curious would the 3 inch spacing look silly?

I used some metal track alignment guides to draw 42" radius curves on a sheet of paper with 3" on center double track curves. To me, the 3" separation between tracks on the curve seem a bit wide. But, I doubt that the 3" separation would look "silly".

On my double track mainline, the curves are 32" radius and the track separation is 2 1/2" on center. I run lots of Walthers 85' passenger cars, and they look pretty good to me rounding those curves.

My guess is that using 42" radius curves, you would only need, say, 2 1/4" on center separations. Nothing silly looking about that.

Rich   

Alton Junction

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Posted by ATLANTIC CENTRAL on Wednesday, March 16, 2022 5:09 PM

It can depend on the equipment you run, but I have never had any trouble with 2" centers on 36" radius and above. 

If you want to be safe, at 40" radius, maybe go 2-1/4" centers.

The prototype sometimes spaces parallel tracks out more than the minimums, straight or curved, depends on a lot of factors.

For our models, I have always prefered keeping the right of way as narrow as possible.

Sheldon

    

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Posted by dknelson on Wednesday, March 16, 2022 5:53 PM

I wanted to retain the 2" centers of my double track main line on the curves, particularly since most of the curves on my layout were tangents on the prototype I follow

I had some old brass flex track that I was never going to use so I created three concentric circles of track on a sheet of plywood: 42" radius, 40" radius and 38" radius.  I then ran (well OK, pushed with a finger) the full length Walthers passenger cars I intended to run looking for interference and potential sideswipes.  42" and 40" were fine.  Maybe there are some long cars that would have issues but not the particular cars I wanted to run.  40" and 38" radius were verrrrry close and it wasn't hard to imagine that even a slight tipping of a car would create a heart-wrenching crunch.

Again holding to 2" centers worked fine with the particular equipment I intended to run.  If you can scare up some swap meet flex track you might want to try doing the same experiment.  

Dave Nelson

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Posted by John-NYBW on Thursday, March 17, 2022 6:52 AM

I have 36" and 38" curves on my double track mainline. I have found there is one place for a potential sideswipe with my full length passenger cars. It is the curve that has a #8 turnout on the inside curve. Theoretically this is actually a 38" radius curve. I trusted it when I laid it without actually checking it out but now I am not so sure. I laid the inside curve first and then made sure the outside curve was 2" outside that all the way around. I am a lone wolf operator so I generally don't have two trains in motion at the same time during an operating session but sometimes I just want to do continuous running and will have two trains going at once. I remember one instance when two passenger trains took that curve at the same time and the inside train grazed the one on the outside curve. 

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Posted by richhotrain on Thursday, March 17, 2022 6:59 AM

Early on in my HO scale modeling, my LHS guy gave me two 85' boxcars and told me to use them for testing purposes on curves. I don't even need to power up the layout. I just put one boxcar on each mainline curve and push them past each other in opposite directions to check for clearance.

Rich

Alton Junction

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Posted by selector on Thursday, March 17, 2022 3:14 PM

By the time a modeler has some history, maybe even as early as a second layout construction, and with a few different locomotives and items of rolling stock, it's likely they have a good handle on what is going to cause a problem of a kind. Clunking into a carefully placed plaster 'portal' on a curve.  Snagging a bridge diagonal brace with a raised pantograph.  In my case, the engineer's injector overflow or the cab roof extension on one steamer, the Rivarossi H-8 Allegheny.  So, I use that and my Walthers heavyweights, the longest things I own for rolling stock.  I do the trials and ensure I have more than just 3mm clearance. I would like it to be somewhat realistic in scale as well....ideally.  For overhead, it's the Trix GG1 with its pantograph.

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Posted by wjstix on Monday, March 21, 2022 10:56 AM

With that high a minimum radius, you're not going to have much overhang even on your longest pieces of rolling stock. I had a prior HO layout that had 42" and 44" doubletrack curves with 2" separation, it had no problems.

Stix

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