wheels are mounted in a bearing box, and these boxes are inserted in an opening in the truck frame. Between the box and the frame is a liner usually of hi strength steel (although there are plastics beings tried now) to allow the axle to flat a bit vertically in the frame. Without a liner between, the bearing box would wear directly against the truck frame, and destroy the frame shape, allowing the wheel to slap back and forth against the mount.
well since it is just about there, you might as well fix the trucks at the museum while it is still there because you can use that extra money for the trucks
not quite sure what you mean by extra money, since there is not any of that ...however, the decision is going to be based on several factors, one of which is the cost difference between doing the work there versus renting a flat car and cranes.