The Lionel MKT No. 600 Switcher used a RED body with WHITE heat-stamped lettering and railroad herald. This engine had operating disc couplers at both ends, but there was no interior illumination or frame skirt. It was equipped with a three position directional unit whose control lever was adjustable from the bottom of the sheet metal chassis, and either one or two axle Magnetraction. Produced only in 1955, it is amazing that there are five variations:

Variation A: GRAY chassis with YELLOW end rails, Type IIE motor.

Variation B: GRAY chassis with BLACK end rails, Type IID motor.

Variation C: Identical to Variation B, but with Type IIE motor and two axle Magnetraction.

Variation D: BLACK chassis with BLACK end rails, Type IID motor.

Variation E: Identical to Variation D, but has a service-station replaced body that has a nameplate on the sides.

Lionel issued this diesel for use on O27 gauge track, but it will operate equally well on the larger radius curves of O gauge track.