Turnout/switch problems

Discussion in 'HO Scale Model Trains' started by RobertInOntario, Jan 29, 2008.

  1. RobertInOntario

    RobertInOntario Active Member

    As you can tell from this pic, my layout once had a passing siding that was created via two curved switches -- one in the lower left and one in the lower right.

    Well, I've had derailments off and on at the lower-right curve. This curve used to be a Hornby turnout but I learned that Hornby's curved switches aren't the greatest quality so I replaced it with a Peco switch -- supposedly the best.

    Well the problems persisted off & on even with the Peco switch. :cry: These problems worsened over the past few days as three of my main locos derailed at this location. Two of these locos are very new, so it's probably the track that's at fault.

    Last night, I made one last ditch effort to solve this. After an hour so or, I gave up and removed the curve altogether, but even this took me 2-3 hours to get the curved shapes right and solve derailments! I will simply use this siding only with the one turnout now.

    I doubt that this Peco switch is causing the problem. I suspect that it's due to how I've laid out & positioned my track. It could even be caused by the location on the board where the turnout was placed as it's become rather uneven now after so much adjustment to the road bed and ballast.

    Just wondering if anyone else has run into similar problems or has suggestions. FYI, I'm not mechanically minded at all so I really struggle with things like this. :confused: I'm sure many other folks could pinpoint the problem right away!


  2. Nomad

    Nomad Active Member

    Rob, have any conditions changed in your train room recently? Heat or humidity? Any thing to cause the track to expand or contract?

  3. ed acosta

    ed acosta Member

    There are several possibilities to look for. Is the derailment at the switch points, or the frog, or beyond to the connecting section. Only way to find out is to run the locos slowly, over and over, until you can see what is happening. Not until you can actually see the wheel hop over the rail will you be able to isolate the condition. Perhaps the rails are out of gauge. I've had it happen on Shinohara turnouts. Maybe the frog troughs needs some filing to clear the wheel flanges. How is the roadbed? Is there any ballast or obstruction that would keep the turnout from laying flat and even with the remainder of the track?

    From my perspective, it appears that the train is traveling through a series of diminishing (tighter) radii. First, the mainline; second the smaller radius on the inside turn; and thirdly, an even tighter radius on the siding. It may be tighter than you think and the trucks on the locos might be restricted. FInd out where the restriction is and you may have to file away part of the truck or undercarriage to clear.

    Let us know how you solve this one!
  4. MasonJar

    MasonJar It's not rocket surgery

    This statement says that something changed - but was it the layout somehow shifting/moving, or did you do a different "behaviour" with respect to the turnout (e.g. running different locos - new ones? (see below) - or running in a different direction that was never run before?). The fact that they "worsened" seems to suggest this was always a problem though...

    Unfortunately, you can never assume that new stuff is properly assembled. The other part of the equation is the gauge of the wheels...!

    As an example, I had a horrendous problem with some passenger cars derailing at a certain switch. I told people it was an Atlas snap switch, and the immediate response (not from this forum BTW... ;) :D) was "Atlas Snap switches are junk!" Luckily, I decided to get an NMRA gauge and check before I ripped it out. It was not the problem, as I discovered when I turned the gauge to the wheels on the passenger car. Not one of the twelve wheelsets was in gauge...

    So please check the locos and everything else that derails there. Even if they are all in gauge, you've at least eliminated them as guilty, and you can be sure it's something to do with the turnout/track.

    There's a thread titled "My loco derails at...", or something similar, that provides a lot of good information on troubleshooting. If I can find it, I'll post the link.

  5. MasonJar

    MasonJar It's not rocket surgery

  6. RobertInOntario

    RobertInOntario Active Member

    Thanks, Loren. That has happened in the past (i.e., last fall when the weather changed from hot/humid to much cooler, dryer conditions), but I don't think it's the cause this time. I think I'm basically trying to resolve an ongoing problem that I've simply been tolerating until now. Rob
  7. RobertInOntario

    RobertInOntario Active Member

    Thanks for all of your comments! Quick update: I've now completely removed the "offending" curved switch and have replaced it with a piece of flex track -- this is working very well.

    The previous passing siding has now become a long siding along the bottom/lower portion of the layout. This is accessed by the remaining curved switch in the lower-left of the layout. This too is working well as it allows me to park very long trains down there -- much longer trains than previously (using the previous passing siding).

    Although I liked having the passing siding and this new arrangement has changed the layout configuration, I'm still enjoying it and it seems to be working well.

    Andrew: I'm going to read and study your responses & info later today.

    Thanks for your help.

  8. RobertInOntario

    RobertInOntario Active Member

  9. MasonJar

    MasonJar It's not rocket surgery

    Then you'll be ready for the *pop* quiz...! ;) :D sign1

    Hope it helps.

  10. Russ Bellinis

    Russ Bellinis Active Member

    Robert, you mentioned that working in that area of the layout has resulted in some rough sections of the table under the switches. It is critical that switches (turnouts) be mounted on a flat surface. It does not need to be perfectly level, but it does need to be perfectly flat. Any bump that puts any sort of twist in a switch, will cause derailments. If you need to change elevations, always do it before or after the switch, never under the switch.
  11. RobertInOntario

    RobertInOntario Active Member

    Thanks, Russ. Good points -- I think that's part of the problem.

    Sometimes I could resolve the derailments by angling the switch, i.e. putting a small cardboard shim under different parts of it. But, in the end, I think I really messed up the area. Sometimes cars or locos would derail right at the frog, but that's probably when the frog was sitting on top of a bump.

    At other times, cars would easily pass through the frog but derail just slightly before or after the switch. I've now tried to improve and flatten out the area.

    This info about having a perfectly flat surface is very helpful. Other sections of track will tolerate a slight bump or change in elevation, but (as I'm learning) not at switches. Thanks again.


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