Front trucks on tender jump the track

[taxmahon]

I have a Bachmann Southern Pacific 4-8-4 with DCC, and the front trucks of the tender continue to jump the track.
I have added weight inside the tender above the trucks, but the problem persists.

Does anyone else had this problem? How can i resolve my issue?

Thank you....
-Robert

[Piyer]

I don't have that model, so what I'm suggesting is just based on a couple of decades in the hobby....

First, is this happening at random places or the same locations all the time? If so, what location and at what speed?

Second, closely examine the truck. Make sure that all the axles are properly seated. With three-axle trucks it's possible for a low center axle to lift an end one enough to bounce clear of the rails. Likewise, if the end axle is sitting too high, it'll bounce clear of the rails.

Third, look at the kingpin - the point where the truck attaches to the tender's frame. Does it swivel freely? Does it have some play to rock side to side and end to end, or is it stiffly mounted? It should not be dangling in the breeze like a flag, but there does need to be a bit of play or else the rigidity of the mount could cause it to leave the rails in curves or dips.

Fourth, check the gauge of the wheelsets. If they are out of gauge, that too will make them wander from the rails.


I hope that helps you solve your problem.

~AJ

[taxmahon]

AJ:
There is no particular spot on the track or train speed that might cause the trucks jumping the track.
The kingpin is not bound up in any way.

However, I never thought about checking the axels on the trucks. I will check that out and let you
know what happens.

Thank you for the advice.

Robert

[rogertra]

The usual cause of the front truck derailing is the lack of flexibility in the wires Bachmann use to connect the loco to the tender.  The wiring tends to slightly lift the front of the tender thus allowing the front truck to derail.

I fix this in two ways and do this to all my Bachmann steam locos as a matter of course.

1)  Make sure as much of the wiring as possible is tucked back either into the tender or the locomotive as possible.

2)  I use two self adhesive weights, available at a hobby store,  to the front of the tender either under the coal load of up in the water spaces either side of the coal load, depending on the tender.

Using both these methods has always fixed the problem for me.  I have something like 30 steam and have no problems with tenders derailing.  Unfortunately, I do not have any weights left so I cannot provide the name of the manufacturer.

Cheers.

Roger T.

[taxmahon]

Roger,
Your advice of placing the weights under the coal load worked. I had the weights directly above the front trucks on the inside of the tender, and moving them under the coal load did the trick. Thank you so much.

-Robert

[taxmahon]

AJ,
I checked the trucks and all was fine.
Another forum member advised me to change the location of my weights to judt under the coal load inside the tender and that worked.

Thank you for your help, Inwas really getting frustratex.

-Robert