The first F-3 cab unit diesels were built in October, 1946. This engine was designed to better accommodate changes in speed and tractive effort, making it ideal for use in freight or passenger service. Included in these F3 Sets are powered A and B units with diesel sound in the A unit, full interior with hand-painted two-man crew, wire grab irons and lift rings, diecast zamac frame and gear boxes, operating headlight , illuminated numberboards and see-through high fan shrouds w/movable fans. Models are equipped for AC operation but include parts for conversion to either DC or DCC operation.