Lurching box cars

Discussion in 'N / Z Scale Model Trains' started by Harpo, Mar 30, 2006.

  1. Harpo

    Harpo Member

    Wondering about a couple of things here. I have one or two cars (the same ones) that seem to lurch fore & aft with some regularity as the train progresses around the layout, especially at low speeds. The location in the train is usually toward the end, furthest away from the loco. I'm wondering, if maybe it may be only a dirty track problem, where the loco itself is lurching, but the action is transmitted only to the last few cars, although I can't see that happening. Or if one car is possibly too heavy weighted, or what... we're dealing with n gauge here, and accumate/mt/kadee couplers which seem to have a fair amount of fore & aft sprung motion anyway.
    By the way, I recently acquired an Atlas RS3. Man! Is this a sweet runner or what? VERY quiet, extremely smooth even right out of the box. I am impressed!
  2. MasonJar

    MasonJar It's not rocket surgery

    You might try checking the rolling characteristics of the car(s) in question. If the wheels do not spin freely, are not in gauge, or are not round :eek: what you might be seeing is slightly different rolling resistance than your other cars. This could give you a forward-backward motion. The weight is also something to check, as you noted.

  3. johnny b

    johnny b Member

    I had a couple a cars that did that too. All thogh the above mentioned idea makes a lot of sense and is likelly the problem , mine were cured when I got a diffent better quality engine that ran a lot smoother.
  4. MasonJar

    MasonJar It's not rocket surgery

    That is also a good point! If your loco does not start out smooth and run well at low speeds, its "jerkiness" can be transmitted down the line. It will be most noticable at the end, as those cars have the "benefit" of all the combined slack.

    One more thing for your list of things to check! ;) :D

  5. davidstrains

    davidstrains Active Member

    Some of this can also be attributed to the pulse characteristics of the "dc" we use on the layouts. Most of the locos that I know of in n-scale appear to run smooth at low speeds with no cars attached. But when you hook 2 or 3 cars behind it you see the "lurches". Pulsed DC will do this as will the modified "DC" we get with DCC. The lurch is the coupler slack being extended and retracted as the pulses hit and rotate the motor. The only way that I know to eliminate this is to have a perfectly tuned local motor, gears and drive assembly. All possible, difficult to achieve.

    I try to start my locos slowly and increase the speed steadily to get them up to a speed where those "lurches" go away. I don't use momentum.
  6. Sonny

    Sonny New Member

    lurching cars

    Some cars mostly Micro Train cars have really frree rolling wheels. They make a spring that you install on one of the bearings of the wheels. That will solve your problem. Mostly it is the last car of the train that has this lurching.
  7. brakie

    brakie Active Member

    If you are using MT trucks/couplers on your cars then it sounds like the "slinky" effect caused by the couplers..My solution is to use MT's axle spring or a old fashion brass pickup for lighted passenger cars..This problem is not caused by cheap engines or DC and can't be fixed with cure all problems with DCC.:D This problem has been around for years.
  8. Catt

    Catt Guest

    I would suggest that you place these cars closer to the locomotive.I think you will find that they no longer exibit the slinky effect (assuming they have MT trucks/couplers that is.)
  9. Harpo

    Harpo Member

    Many thanks for the suggestions. I have eliminated the car that seemed to be causing the most problems; it had a cast metal floor which made it about three times heavier than anything else. Stripped it for parts, actually...the trucks were fine. Running without it has eliminated about 90% of the lurching, but as time goes on I will try the axle spring idea as well, when time allows. Again, many thanks!


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