Help : My loco has a death wish

Discussion in 'N / Z Scale Model Trains' started by RealizE, May 22, 2008.

  1. RealizE

    RealizE New Member


    I had hoped that my first post would involve showing off my layout progress, but unfortunately I'm here to ask yet another question about derailments (my apologies). I've been searching for a good while now, but I can't seem to determine what my issue is.

    I've got your standard N guage manual Peco insulfrog medium length turnouts (2 left, 2 right) that are causing one of my locos to spectaculaly derail. Each time it attempts to pass straight through the turnout (ie, not turning left/right off the mainline) the loco will flop onto its side, roll down the embankment and fall a few feet to the floor.

    The track is all brand new, the approach to the turnout is straight and only one loco has the problem. I have 3x Minitrix 2-6-0 steamers that have no problems, but I have recently aquired a 2nd hand LifeLife GP18 that can't get through.

    At a very very slow speed it makes it through and pushing it through by hand, I cannot feel any resistance or anything catching. At operating speed, the train stops and then flops onto its side. I've run it through 1000 times and I cannot visually see what is happening. There doesn't seem to be a pattern - sometimes it will fall with the front trucks over the frog, sometimes the rear.

    Looking at the wheels on the loco, the only thing I can think of is that the flange on the wheels is worn down and it is rolling sideways over the edge of the frog - can/does this happen? The minitrix steamers have a much larger wheel flange, but I expect that is more to do with the older design. Since I don't have any other locos the same age, I've got nothing to compare them too. That said, they are not a lot different to my Fleischmann cars.

    Can anyone suggest what might be unique to this loco that would be causing the problem? I've spent several nights watching it trying to see what happens, but since it only happens at speed, it's almost impossible to catch it as it happens.

    Once again, I'm sorry for asking a question that has no doubt been answered 1,000 times.

  2. eightyeightfan1

    eightyeightfan1 Now I'm AMP'd

    Well........1001 times now.
    Check the underframe. There might be someting loose or dragging thats catching the frog as it passes under speed. Could be as simple as the trip pin on the coupler catching. When running slow, the frog might just push the trip pin out of the way. Under speed, it might be catching.
    Hope this helps.
  3. Herc Driver

    Herc Driver Active Member

    I'd wonder about the wheel flange too...but for a sudden rail departure like you're describing, I agree with 88Fan1 and would look to see if something is dragging. I would think that if your wheel flange is too large, it would depart no matter what direction or rail it's traveling. Does it derail when you send it the other direction over that same Peco turnout? Maybe there's a small burr or bent rail that it hits when the engine is only going in one direction? Also, double check the wheel set dimensions...maybe one set is just too tight and causes the derailment.
  4. RealizE

    RealizE New Member

    Thanks for the replies, guys. There's definitely nothing coming incontact with the track except for the wheels.

    It does the same thing on all 4 of the turnouts, but tt only derails when heading into the turnout (ie, in the direction that allows you turn off). Heading the other way with the siding leading into the main line shows no problems. Turning the loco around and running in the same direction also causes it to comme off the rails.

    Herc : When you say "wheel set dimensions" I assume you are meaning the distance between the pair of wheels on a common axle?
  5. jesso

    jesso Member

    When we first setup the club layout at my house, I had an SD70Mac that when it got to the frog it would just fall over on its side. We found that the space between the track and the plastic rails on either side of the frog to help guide the train though whichever direction the train was going were too wide and as the flange of the wheel would go though, there was enough room for it to move around and would cause the other side of the truck to hit the front of the frog and make it wreck. We glued a VERY thin strip of styrene to the inside of that plastic guide closest to the rail and that fixed the problem. In fact, we have now done that to every switch on the layout and we never have derailments anymore. All the switches on the layout are peco mediums.
  6. RealizE

    RealizE New Member

    Thanks Jesso, it sounds like that will be my problem.

    I guess I should have waited for more replies before I started opening up that gap with a nail file :(

  7. CraigN

    CraigN New Member

    Buy an NMRA N scale standards gauge.

    With the gauge you can check to see if your wheels have the correct spacing. You can check other stuff with it too.

  8. logicman

    logicman Greybeard


    I go with Jesso.
    (Not that he needs my endorsement.):mrgreen:

    It's a known problem with Peco turnouts and some rtr brands, here in the UK.
    Old Hornby + new Peco = derailment.

    (Note to Hornby: my lawyer is on 24/7 standby - he needs to be.)
  9. Herc Driver

    Herc Driver Active Member

    Yep you guessed right - and I'm glad you could figure that out from my fuzzy logic writing. I didn't even think about the frog being too wide...that's really an interesting idea to check out.
  10. logicman

    logicman Greybeard

  11. RealizE

    RealizE New Member

    Well, the extra plastic strip worked a treat. All my locos are now sailing through without any problems!

    Thanks for the help, gents!

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