U.S. Prototype Double Track Spacing

Steve Mann Mar 26, 2013

  1. Steve Mann

    Steve Mann TrainBoard Member

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    What is the distance between the inner railheads on U.S. double track? I have the parallel spacing tool from MLR but I wasn't sure if that was prototypical or not. I ask for the inner rail spacing so if the MLR one is wrong I can make something out of styrene. I'm using the Peco #7's for the crossovers but it seems the track kinks just slightly at the joints to the ME C55 while using the MLR tool.

    Let me know if you have the prototype's standards and any tips.

    Thanks,
    Steve
     
  2. glakedylan

    glakedylan TrainBoard Member

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    Steve greetings! Peco like Atlas C55 works on a 1.25" center to center spacing in crossover with #7 turnouts. Knowing that N Scale is supposedly 9mm rail to rail separation one can do the math, given the correct translation of mm to inches. I hope this helps. Sincerely, Gary L Lake Dillensnyder
     
  3. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

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    Steve-

    Usually such measurements will be seen on blueprints as being centerline to centerline.

    I might have something Northern Pacific somewhere. A couple of pieces buried from the UP. I do have a lot of MILW, and did grab one sheet which was atop the boxes. It shows fifteen feet centerline to centerline on tangent track. Also, thirteen feet yard tracks.

    I cannot state absolutely if there was any sort of engineering standard minimum track spacing across the country. However, it would certainly seem so, in order to have all the same clearances for cars and equipment.
     
  4. maxairedale

    maxairedale TrainBoard Member

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    That would depend on what era you are trying to model. I say this because as time has moved along and with maintenance and changes in locos, tracks have gotten nearer to each other.

    In November 1992 CSX secured the services of Union Pacific Challenger 3985 and disguised her as Clinchfield Railroad 676 (One number higher than Clinchfield's last Challenger 675). She was used to pull the 50th Anniversary Santa Express train from Shelby, KY to Kingsport, TN. With all the safety measures that CSX took for that special event, the loco hit a string of hoppers on a curved siding, a section of track that Challengers had pass over for many years. The siding had been repositioned during a rebuild. There was no longer a need for the extra clearance between the two track since the big locos were not used any longer.
     
  5. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

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    I'd sure be interested in knowing a 'why' for doing this. It doesn't gain anything in space savings. Usually in double track territory, the RR owns between 50 and 100 feet r-o-w width. With exceptions, but those numbers are pretty much an average. Or could that track work have simply been incidental, not normal? Or even an error?
     
  6. Steve Mann

    Steve Mann TrainBoard Member

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    I thought I read somewhere on here that 15' - 16' centers were an average. I model the Santa Fe in the 93-94 era double track on the Marceline Sub. The problem I have with using track centers is there's more room for error with me being lazy. Seems time consuming to measure the center of each track, then measure between the two. haha. Do Pecos require any spacer piece of track on the diverging routes for crossovers or can you just butt them together?

    Thanks for the help. Looking at video and pictures it sometimes looks wider than 15'. Must be a matter of perspective. On foam it looks a lot closer together probably because I dont have any scenery or backdrops for points of reference to get that appearance of that spacing.
     
  7. Jolly

    Jolly TrainBoard Member

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    The Army manual show 15' on the centerline, in curves For each degree of curvature, side clearances shall be increased 1½ (1.50) inches
     
  8. Inkaneer

    Inkaneer TrainBoard Member

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    The distance between adjacent track has increased with the advent of longer cars. Sixteen feet is now pretty common and in areas where a third track has been removed the distance between the two remaining tracks has increased to twenty feet or so. This allows work equipment to work on one track without blocking the other track. Twenty feet corresponds to 1.5 inches in N scale which is also the spacing specified for Ntrak modules.
     
  9. randgust

    randgust TrainBoard Member

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    Geez.

    OK, while a lot of things change, a lot of things don't, either.

    When in doubt for your railroad and your area, it's increasingly easy to just jump on Google Earth and check it for yourself. There's a HUGE difference between what used to be done and what is done today. Yards were built tight, not anymore. You're looking at current standards of 15' in most situations, but if you get into it you find that steam-era spacing on multi-track main lines was as tight as 12'6".

    Altoona, PA, right at the signal bridge: 13' centers PRR (I've seen this a lot)

    Flagstaff, AZ, in front of the depot: 18'

    Joliet, IL (ATSF) right in front of the depot (Lincoln Highway) 13' (legacy)

    Rochester, NY (ex-NYC four-track area) 13' just west of Amtrak station

    Pittsburgh: 17' just east of station

    I use 1 1/4" and cut my switches to do it, that works out to around 17'. I'll cramp the yard tracks down to 1 1/8 which is 15 feet. Most layouts have their main lines set way, way, way too wide because of the switch geometry and no other reason.

    The typical 66' wide right-of-way in the east could get eaten up pretty quickly; two main tracks, maybe two sidings, then the roadbed sloping down to a ditchline, the pole line right-of-way, then the fenceline. Most railroads in the east in the steam era - particularly NYC and PRR, ran 'em close and unless there are major changes, they are still that way today. And they aren't deliberately getting closer; if there's any room to do it they are removing old center tracks, spacing them wider, etc. if they can. But for the most part they're stuck with the way they were originally built in legacy areas.

    I'm not going to argue, but I am going to suggest you use the Google Earth tool and go out and zoom in and measure yourself. It's fun and easy.
     
    Last edited by a moderator: Mar 26, 2013
  10. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

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    It might be helpful to know the chosen to be modeled time frame. For example, that spacing I noted last night was from a company blueprint updated during the 1970s.

    Naturally things have spaced out as years have gone by. Not just longer cars as a consideration for curves, (which is why I questioned that collision on a curve last night as being an anomaly. They do make mistakes in both engineering and on-ground work), but wider as well. We have gone from post-WWII widths of under eight feet, to seeing common sizes well exceeding ten feet. That is stated interior width, so even more if you take an exterior dimension.
     
  11. TJS909

    TJS909 TrainBoard Supporter

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    Great info. I'll be needing this soon to build my new layout.
     
  12. HemiAdda2d

    HemiAdda2d Staff Member

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