In helping a friend rebuild his Lionel Postwar 2360 GG1 (Version E), I found that both front and rear trucks were jumping off the rails on curves almost continually. And switch tracks? Every time it would go into a turnout, it was toast. I read an article in one of the OGR forums that showed the use of a spring and fiber washer on the truck alignment tab, and although it helped quite a bit, the front of the trucks were still bouncy and still not making it through a turnout reliably.
After investigating how the spring tension was affecting the trucks, I came to the conclusion that a second spring/fiber washer combination installed on the truck mounting screw would put downward tension on the front of the truck. It worked quite well (see photos). The same fiber washer (Lionel #630-8302-P15) can be used but needs to be cut flat on one side to avoid conflict with the motorized truck (I used my grinding wheel for that). I used a Lionel #600-1015-054 spring for the tension, but any spring in your parts drawer with enough tension and a diameter small enough to sit behind the head of the truck mounting screw is fine.
Looking at the photo of the installed spring and washer, you can see that the spring pushes on the head of the truck mounting screw, creating upward tension on the rear of the truck which (pivoting on the alignment tab) forces the front wheels of the truck down onto the rails. The spring on the truck pivot balances out the tension nicely. Having the spring/washer combination at both locations makes the trucks very stable.
~ We're not afraid of switch tracks anymore.
