Lionel Trucks

It would help to know which specific cars, there are several types of trucks.  I don't know of any significant issue with Lionel trucks vs. other brands, rough handling can break any of them.

I would replace Lionel trucks with new Lionel trucks. If you try and use another brand the mounting stub size and length may be different and that will require some fitting to work.

First time I've heard of broken trucks from any manufacturer. Some that don't work well, but not broken.

Unless you have a desire for Kadee couplers, and understand their use with three-rail trains, which I'm slowly learning myself, I would stick with Lionel trucks on Lionel cars.