This was a new design by Lionel produced on a clear plastic mold and painted GREEN. 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. The motor is controlled by an switch lever under the car. 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. The Aquarium Car was last available in 1962, but was later released by MPC in 1981.
There are four variations:
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.