The Lionel Rock Island FA A Unit No. 231 was produced from 1961 until 1963 on a sheet metal frame that had solid non-operating couplers. This diesel has a two-position directional unit whose control lever is adjustable from the top, and two axle Magnetraction, an interior light, but no horn. There are two variations:

Variation A: has a BLACK painted body with a RED stripe across the middle with a smaller WHITE stripe at the roof line and heat-stamped lettering. Used a Type IIA motor. 1961-1962
Variation B: has a BLACK painted body, but no RED stripe. Has the roof line WHITE stripe and heat-stamped lettering, and used a Type IIC motor. 1963

This engine was issued to run on O27 track, but it will run equally well on O gauge track.