The Operating Traveling Aquarium Car No. 3435 was greeted with scorn by collectors when it was released in 1959, but this criticism has mellowed with age. This was a new design by Lionel produced on a clear plastic mold and painted GREEN, and there is a friction motor on the inside that turns a film with fish on it so that it appears they are swimming in a tank. Came with early AAR trucks with disc couplers and early versions would have GOLD heat-stamped lettering that later would be rubber-stamped on in YELLOW. It was last available in 1962, but has since been released by MPC in 1981.

There are four varitions:

Variation A: Large "L" with GOLD circle and lettering: "Tank No. 1" and "Tank No. 2". This variation is rare.

Variation B: Same as A, but there is no circle around the "L".

Variation C: Has GOLD lettering but no circle around the "L" and no tank designations.

Variation D: Has YELLOW rubber-stamped lettering with no circle and no tank designations.