Very durable- these 4500 series cars are meant to be played with. Metal ladder/ walkway, platform, buffers & base. Nothing really delicate that can be broken with NORMAL use. Two axles means easy rerailing. Highly recommended!
However, THIS is an early version 4501, with the Primex couplers! NO, it is NOT going to be played with- It is going right into my collection. An NOS example like this, along with its box, needs to be kept in mint condition.