Track Cleaning Car No. 3927 is the only one of the small units that is not self-propelled. As such, this car would need to be pulled along the track by a strong engine. Available from 1956 until 1960, the motor in this unit drives the rotary cleaning sponge beneath the unit. The motor is controlled by a switch that projects through the top of the body.

Manufacture of this car caused Lionel to replace the track cleaning fluid that had been used up to this point. It was flammable, and because of the sparks generated by the motor and the center rail pick-up could not be used with this unit. Lionel replaced this fluid with the No. 3927-75 which is non-flammable.

The ORANGE body has BLACK heat-stamped lettering and movable wiper assembly on the rear of the unit. There is a solid die-cast non-operating coupler on the front of this unit. This cleaning car came it with two bottles, a track cleaning sponge, and two cotton wipers, and is often found with these parts missing. Replacement parts are available, but the original bottles had "LIONEL / TRACK / CLEAN" painted on them. There are no variations.

Two instruction sheets were issued for the track cleaning car. Both used No. 3927-44. The first dated 8-56 used LIGHT BLUE paper and DARK BLUE ink. Three pages of this sheet are shown below. The second was issued 8-58 and used DARK BLUE ink on WHITE paper.