Hi Dan,
I removed the springs on these problematic trucks, and stretching the existing springs did not solve the problem...they still opened-up under normal operations. So I replaced the springs with ones I found in ball point pens. Took a while to find the right springs, but I eventually found ones that are slightly longer, wider in gauge and considerably stronger then the originals.
These seem to be working, but keeping my fingers crossed. I am trying to find replacement parts for this truck by Lionel Support does not carry these in their inventory. In fact, none of the half dozen parts dealers I contacted have them in stock.
If anyone knows a source for these, please let me know. The Truck Part is #610-9011-100 for the 9011 Lionel Baggage Car...vintage 1993,
Thanks.
Urbie