I use under bed storage bins from a variety of makers under my layout. I pad the bottom with thick fabric from JoAnns. When I want to run I slide out and take individual cars or take the whole bin to a ready area. The bins on the bottom of stack are wheeled. Only 2 high for ease of handling. I label the ends so I know what’s where.
The engines are separate, mostly non binned for now but close to the cars most likely to be run together example Santa Fe F3s close to Santa Fe passenger set.
If you like the idea of using them on or under a layout you might be able to use the same bins to move your trains and save a few bucks.
There are many sizes so check what length works for you.
Im using those with boxed and unboxed trains.