36 ton shay trucks

[Bigworm]

Hello all, I'm fairly new to the train world so please bare with me. I recently acquired a older 36 ton shay and the trucks were shot, so I replaced them with spectrum #88999 die cast trucks and the train ran smooth for about six laps (64' of track) and then started jerking real bad and train looses most power like its shorting out. My trainpower 6200 controller shuts of the circuit, others engines work fine. My track is brass and very clean. When I remove the trucks from the chassis and run them by them selfs they run very good with no problems but when installed back on chassis same problem occurs the train is not sound equipped. I've tried running the train without the two wires to the trucks and no difference. Is there an internal short somewhere? Does the chassis pickup power from the trucks other then through the wheel pickups? Just weird how the trucks work good when not on engine. Anybody else have this problem? Please help. Thanks

[GG1onFordsDTandI]

I don't actually own a Shay to say for sure, but it may be as simple as spinning one axle and/or the truck 180 degrees.
At least one wheel on a set (axle, and 2 wheels) is isolated from the axle. If they are not positioned on the same side of the truck, a short occurs. If the truck is metal, it is touching the axle, therefore live with electricity... So, if the loco chassis is also metal and "live"(usually), and the "live" truck frame is connected to it, they both must feed off the same rail. Why would it run at first? I suspect it took a bit for good contact between the two to happen. New paint wearing off somewhere may have delayed the shorting contact too. Also look for wheel edges touching the die cast truck, especially wheels which are isolated. Even if its a plastic chassis and plastic truck making sure any isolated wheels are all on the same side is crucial.
Hope that makes sense to you.... and helps solves it.    

[Bigworm]

Ok for starters GG1 you were on the right track it WORKS!!! Thanks. On these it doesent seem as tho you can turn the axels 180 on the trucks due to the novelty driveline/gearing/pistons. So I rotated the truck top plate 180 degrees and so far been running smooth for an hour now. I thought I did this already and the trucks ran opposite of each other so I figured that couldn't be the problem. Thanks again it makes for a good Saturday!!!!

[JerryB]

Also be aware that the TrainPower 6200 is only rated for 35Va. That is less than two amps. This is marginal power for large locomotives, even the two truck Shay.

Happy RRing,

Jerry