I found the Weaver plastic-truck wheelsets were over-gauge compared to Lionel ones.
How so? not by derailments but with friction. During my days of floor layouts, I would build large loops that ran from room to room, using 072 curves so I could run long trains. One of those was a unit grain train comprised of Lionel and Weaver ACF hoppers, pulled by a Pullmor-motored SD40 and a Williams SD45 (when they were equipped with 540 motors). This whole arrangement was powered with a MRC Trainpower 027, an admittedly under-powered transformer.
I noticed that if I tried to increase power to maintain speed when the Weaver cars were traversing the 072 curves (they ran grouped together in the train), it would often trip the breaker. It wasn't until I was able to repeat the results with a pair of K-Line S-2's (which aren't known for drawing much current) that I started comparing the Weaver trucks with the Lionel ones, and found that while the back-to-back gauge was the same as Lionel, the flanges were much thicker, making the wheelsets overall over-gauge.
The additional friction manifested itself in 072 curves, where a sufficient number of wheelsets could "gang up" and raise current draw beyond what the little MRC could provide.
---PCJ
