The Lionel Santa Fe No. 634 Switcher was issued in 1963 and again in 1965 and 1966. This BLUE engine initially came with YELLOW safety stripes on the front and rear, but later issues would not have these stripes. It was equipped with a two position directional unit whose control lever was adjustable from the top of the body that was mounted on a sheet metal frame. This engine was powered by one Type IVA motor, and had a solid plastic coupler on the front, and a die-cast solid coupler on the rear. There are two variations:

Variation A: Has the safety stripes on the hood and the back of the cab and also had a headlight lens (1963 and 1965 production).

Variation B: Without the safety stripes and no lens (1966 production).

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