Overly sensitive GG1

Discussion in 'HO Scale Model Trains' started by Myowngod, Apr 10, 2007.

  1. Myowngod

    Myowngod Member

    I have a Broadway Limited GG1 and the leading and trailing pilots (4 wheel trucks) seem to be very sensitive and hops off the slightest imperfection in track work. I've tried to make the track work as bullet proof as posible but through some switches it jumps all the time and joints between flex track section it seems to jump randomly. I am using code 83 track, this is the first time I'm using it. I never thought it would be so sensitive to track hickups. Has anyone experienced this with your GG1 pilots? And if so how did you remedy it? Do I adjust the spring somehow? Or just keep tweaking the track for the rest of my life?

  2. ed acosta

    ed acosta Member

    Overly sensitive GG-1

    I don't have any experience with the Broadway Limited model, however since no one else has come forward, perhaps I can help.

    The wheels on the pilot truck might be out of gauge. Check and see if you can twist and push the wheels together or apart, as the case may be.

    Or, maybe the truck does not have enough weight or spring tension to keep it on the track. If its a spring, try stretching the coils to add more tension. Is there room for weight?

    Does the truck slide laterally without interference? Also, check to see if the truck can pitch up or down. This would be indicative of a design problem which may require a little filing or modification to prevent any interference the truck and its wheels may have with the frame. Is the truck able to roll a little side-to-side?

    Hope this helps!
    -Ed Acosta
  3. pgandw

    pgandw Active Member

    Some engines will be more sensitive than others. But 1st things first.

    1) Since it "jumps" at the joints of your flex track, that suggests that there are subtle kinks or other problems at the joints - the rails don't line up in a perfect curve or line. The best way to detect kinks is to get your Mark 1 eyeball as close to rail level as you can and sight along the rail. Adjust the position of the last inch or two of the flex track until it does line up perfectly. Then glue the track in place using latex caulk. Recheck rail alignment before the caulk sets.

    2) Ensure rail joiners are tight; use needle nose pliers or new rail joiners to correct.

    3) If using Atlas or other springy flex track, joints on curves need to be soldered while the ends are still straight. Soldering with the 2 rails and rail joiner in place allows for a strong joint that will maintain alignment despite the "spring" of the track.

    4) If using ME or other stiff flex track on curves, you must pre-bend the track before fastening it down. If you can't bend the last inch into a smooth curve, then cut off that inch. You don't need to solder the joints of stiff flex track; they hold the curve on their own once pre-bent.

    5) Use a straight edge on the top of the rail to check for vertical misalignment. If the light peeks out between the rail and straight edge, or the straight edge rocks on a high point, there is a vertical bump or dip that needs to be corrected. Usually, shimming the low point with post card material or similar works. High points mean that the ties will have to be carefully shaved down to a lesser thickness.

    After 1-5 are done, run your finger nail across the joint on the inside corner of the rail top. If you feel any disturbance, very lightly file the joint smooth. Good trackwork takes time and patience to get it right.

    Next get an NMRA track gauge. Check all the wheels on your locomotives. And other locomotives. And other cars. All wheel sets need to pass the NMRA gauge check. Also check for the wheels not centered on an axle or wheels that wobble when they are turned.

    Last step is the turnouts.

    1) Use the straight edge to check for vertical irregularities again. Sometimes frogs (where the rails cross) are either low or high. Points (the movable pieces) need to fit tightly against the stock rails, both horizontally and vertically.

    2) Check all areas of the turnout with the NMRA gauge. Turnouts generally work better if track gauge and flangeways are on the narrow end of the allowed tolerance.

    If you have fixed all the above and you still have problems with ONLY the GG-1, the only possible area left is the design of the pilot trucks. If they are still derailing, you probably need to add a little weight to the pilot trucks or increase the downward pressure. Increasing the spring pressure will reduce the traction of your engine, so only do this as a last resort. But reality is that increasing the downward pressure is fixing a sympton, not the actual problem.

    Hope this helps

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