Shinohara double crossover porblem

Discussion in 'HO Scale Model Trains' started by thedowneaster, Mar 14, 2009.

  1. thedowneaster

    thedowneaster Brakeman

    I recently installed a code 100 shinohara double crossover switch.

    Pic of similar:

    The problem:
    Genesis SD70MACs and Walthers Superliner cars short circuit over the points. These turnouts have live frogs so both the curved point and straight point have the same polarity. Somehow the wheels are rubbing on the points while passing by. This doesn't cause the train to stop but will be a problem for DCC I think.

    NMRA turnout terms:

    Does anyone use Shinohara turnouts and have this problem?

  2. steamhead

    steamhead Active Member

    Does this problem happen only when taking the diverging route, or on the straight section as well..?? I had a similar problem with 3-axle trucks on a brass steamer tender I have. Turned out the wheels were too thick and the turnout too sharp for them. They only shorted when taking the diverging route. I went to #6 turnouts and fixed the problem. Not an option in your case. You can do one of two things: Isolate the closure rails from the frogs, and make sure the throw bar is isolated from the points as well, or see if you can find thinner wheels for the troublesome engines and rolling stock. You might check the gauge on these wheels before taking any other measures. Good luck..!!

    BTW...I believe this only occurred on a couple of Shinoara turnouts I had....Seems the gaps between the points and the stock rails are just a tad on the narrow side.
  3. thedowneaster

    thedowneaster Brakeman

    The problem is on the straight run through. I have not even tried making a crossover yet! I hate to modify the rails, but I don't think I have a choice now. I wish they had isolated the frogs like everyone else does!
  4. Wastrel

    Wastrel BNSF fan

    Take the time and isolate all your frogs. You will be much happier in the long run.
  5. thedowneaster

    thedowneaster Brakeman

    I agree....but after further review, Even after I isolate the frog the points are still soldered together. Thus they will always have the same polarity, and the risk of short continues.

    I found the problem!
    The rail is so soft that when it short-circuits the surface becomes pitted and jagged. This further narrows the gap between the stock rail and points. The wheel backs were also pitted. I took out the trusty high speed Dremel and thinned and polished the outside of the points and the inside of the stock rails. Once everything was nice and smooth the turnout began to work properly for all railcars!
  6. steamhead

    steamhead Active Member

    Good to hear it's working..!! Did you check the gauge on those wheels..?? If they are narrow the problem might show itself again, and you'll be grinding those points & stock rails forever....
  7. thedowneaster

    thedowneaster Brakeman

    Indeed....I think I need to get a real nmra gauge.

    I still can't imagine that a Genesis engine or a new Superliner car would be out gauge though.
    I think my outdated Shinohara code 100 turnout has a problem with nmra RP-25 contour wheels. Because the flanges are thinner, the wheels must have more side-to-side movement...thus increasing the potential for short circuit.
  8. pgandw

    pgandw Active Member

    Actually, you would be very surprised at how many new pieces of rolling stock come from the factory with wheels not quite at proper gauge. We don't pay enough for our models to be hand checked for all the things that might go wrong. The quality is in the hands of the Chinese assembler.

    Add to those mis-gauged at the factory, the case where the gauge gets changed by the harsh handling in shipping - packed into the box, packed into a bigger box, loaded into a container, sent via ship from China, unloaded and trucked, unpacked and repacked at importer, distributor, and hobby shop.

    FWIW, the RP25 flange is substantially thicker than it's predecessor knife-edge NMRA flanges. This would cause the RP25 wheel to be slightly more likely to short out with the back of the wheel touching the open point.

    The ideal fixes are to
    • correct the wheel gauge to NMRA spec - right in the middle of the tolerance is usually best
    • re-wire and gap the turnout so that the points are insulated from each other, and electrically tied to the adjacent stock rail. This makes the open point and the stock rail the same polarity and eliminates short circuits from this cause. This wiring scheme also allows the open point to be physically closer to the stock rail than NMRA spec for improved looks.
    For the ultimate in turnout reliability and looks while still using NMRA wheels, hand lay or adjust turnouts to HO minimum track gauge. This produces minimum width flangeways (better looks) and more support for the wheel tread through the frog (fewer derailments). In additon, wire the points as above, insulate the frog and power it from a contact on the turnout throw. Just these 2 items along with checking and adjusting all parts of the turnouts and wheels to the NMRA gauge will make your track and rolling stock very close to derailment-free.

    my thoughts, your choices
  9. VHenry

    VHenry New Member

    Double Cross Over Fix

    The short is at the frong end of the rails were the inner rails diverge. There is a long drawn out explanation on how to cut gaps and wire around the problem, however for my two cents and what has worked for me is to "paint" the inner diverging rails at the frog with a clear epox, or finger nail polish. You only need to paint to the point where a wheel will not contact both rails at the same time--very short. This has worked for me. It will eventually rub off over many runs across the that section of track. Just repaint the area, let dry and run again.

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