Nov 052013

Hard Times for Hand Laying

I’ve hand laid a 3′ section around a 24″ radius corner. There are some minor dips in the track. Proto:87 cars run fine. A 6 axle loco with P:87 wheels won’t make the curve. It’s obvious now why you need smooth flat track or some sort of working suspension. The 6 axle loco really suffers here, because a minor dip on one axle will cause the other two axles to raise. Generally what is happening is that the center axle raises and the rear axle kicks out (no significant flange to keep it on the track). Possible factors for the problems:

  1. Tight Radius.
  2. Not flat track
  3. Incorrectly gauged wheels or track (I think I’ve got the gauges right though)

How do I Proceed?

Now I’m faced with a decision on how to proceed. I think I need to give something up to get something working. My options as I see them:

  1. Test again with 4 axle locomotive. I’m thinking the 4 axle loco will be more forgiving. I need to order some wheels to do this.
  2. Switch to flex track. It is easier to lay smooth track with and I’ve successfully tested 24″ radius curves with flex track and 6 axle P:87 locos.
  3. RP-25. My 6 axle loco with RP25 wheels works just fine.
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Greg Amer

  18 Responses to “Hard Times for Hand Laying”

  1. Hi Greg,

    Have you tried the Proto87 Stores Easy Rider suspension stabilizers: They’re designed for rolling stock, but can be adapted to locomotives.

    Is that a Kato SD40-2? If so, there should be some rockers on either side of the bolster pins that allow the trucks to pivot up and down along the direction of travel, but restrict movement from side to side. Shave these off, then attach the Easy Riders, one pointing in the direction of travel and the other pointing towards the sides. You may need to get a little more creative than this, but it ought to give your locomotives enough flex to deal with small inconsistencies in the track.

    Good luck!

    - Chris

  2. I am also looking to switch from HO to Proto-87 but I have few issues:
    1. The major one is steam locomotives: where do I find replacement traction wheels, plus my steam locomotive is European, not American and has wheel size of 1400 scale mm (55.12″)?
    2. Another one is similar with European passenger cars having wheel diameter of 980 scale mm (38.58″) and freight cars with 900mm wheels (35.43″) while here in America the wheels are only 36″ and 38″. Worse with locomotives, it’s not merely a coupler height issue but gearing.

    As of six-axle loco derailment issues I would agree with Ian Clasper but add to that. I am not sure about North America, but European minimum acceptable curve radius is 160m, or 500m (72″ in 1:87 scale). However there is one more consideration: buffers. If on S-curve the corner sway of cars exceeds 360mm (the size of buffer plate, the buffers will go past each other) and at the end of curve the train will derail. There is definitely no such problem in North America as trains have no buffers, but going similar radius to this one I guarantee: no derailment would occur on any long rolling stock like Schnabel car or long rigid wheelbase loco, something like DD40x.

    P.S. On my layout I use minimum of 75″ mainline curves and planning to increase 36″ to 48″ radius for “non-prototypical turnaround area” to complete the oval in small space. That turnaround area is preceded with easement curve to avoid lateral sway of car corners as my European trains have buffers, but that is unlikely to help with wheelsets where everything is precisely scaled down from a prototype: if the curve is tight for individual truck, its tight despite of all the easements that precede it. The major factor preventing from going to proto 87 though, is I like steam locomotives, maybe someone knows any technique to correct steam loco wheel profile (lathe, etc.)?

    Thank you.

  3. Have you tried shimming it flat. It would be like the prototype when the re-align a section of track. It could also save you the time of having to re-lay it.

  4. Greg,

    I am surprised to see such a big gap between wheel and rail.

    How are you preparing your ties? Definitely getting them flatter will help. Also 24″ is very tight for six-axle units, so if you are able, you should look at getting over 30″ at least. I believe Chuck Johnstone of Calgary was running un-compensated 6-axle diesels through 30″ radius before he tore his layout out to switch to steam.

    • I reached out to Chuck to confirm what I remember… Stay tuned.

    • Hi Rene,

      The second photo of the wheel is after it has kicked out. I layed the ties on Homasote and sanded them to what I thought was pretty flat. The problem came when I spiked stuff in. Spiking every tie to the roadbed really exaggerated any discrepancies in the roadbed or tie height. I think it would run OK with a 4 axle loco, but I really want to run 6 axle. I can run axle easily around a flex track 24″ curve, so I need to be as consistent as flex track or use flex track.


      • Hi Greg,
        It’s amazing that you can get the big power to negotiate those tight curves on flex track! I did check in with Chuck Johnstone, and he was running them through 40″ minimum radius, but felt sure 30″ would be no problem. If you can spare the space, I really encourage you to broaden out the curves.
        Best of luck!

        • Thanks Rene,

          After running it around the 24″ curve several times I do notice that sometimes the wheels do not touch, which is more likely going to be a cause of derailments. I need to try again with a 4 axle loco when I get some wheels for one.


  5. The width of RP-25 wheels versus P87 would seem to keep equipment on the rails in tighter curves.
    Seems vertical deviations both parallel and perpendicular to the rails must be kept within the depth of a P87 flange for everything to work properly. Can wood ties be reliably sanded to that level of precision?

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