This a Flyer-type problem, dealing with a tender that tends (no pun intended) to “twist” or “rack”. I don’t know how to best describe it. As you know, both left and right wheels of the tender need to sit flat on the track for a Flyer to pick up power.
I have one tender that wants to lift off the track because it “twists”. It will lift off the track at times, just enough to break contact, especially on a corner. It’s not warped and the chassis is not twisted. The amount it twists is almost undetectable to see just watching it, It’s very slight.
It HAS been rewired, and I suspect that the new wire going from the tender to the loco is too heavy, i.e. too heavy of a gauge of wire was used. Could it be that the wire is just too stiff and not allowing the tender to sit level? The tender has the orignal factory weight in it.
Jim,
You may be onto the problem with the wiring. If it is not flexible enough or not long enough to allow the tender free movement, that could definitely cause the problems you are having. You might also check the tender trucks to make sure they swivel freely. If they are too tight, that might also cause the wheels to lift in curves.
Using too heavy of a gauge of wire will definitely cause that problem. I have a 312 that was once wired with the extremely stiff “rainbow” wire normally used for accessories that wouldn’t stay on track through a turn for anything. I forget what I replaced it with, but it works fine.
By the way, the problem is also present if you use a thick walled tub for the S-I-T unit. I have seen many engines that wouldn’t because someone replaced the original tube with a piece of fish aquarium tubing.