My childhood train was a Marx 999 freight set. I still have it and the box. It spends most of its time on the train room shelves waiting its turn on the layout.
The set was the basis for my existing train layout that stared in 1977. Four Lionel 248 and 249 plastic 2-4-2 locos were added the make operation of the turntable and two loops with relays to allow two trains per loop have enough train population for running.
The original 999 engine has been retired with a worn motor gear but has been replaced with another Marx 999 engine.
Charlie