Alco re-designed the FA-1/FB-1 in 1950 to have a dual purpose (freight or passenger) carbody locomotive to compete with EMD's F-7/FP-7. The components used in the FA-2/FB-2 (DL-212/DL-213) were essentially the same as the FA-1/FB-1 in its final specification (DL-208C/DL-209C), including the 1600 hp Model 244D prime mover, GT581 main generator and GE 752 traction motors. The carbody was lengthened by two feet to make room for a steam generator at the rear, and in order to make room, the radiator assembly had to be moved forward and shortened. The radiator fan drive was shortened, and the air compressor was repositioned. Under the frame, there was only room for the fuel and water tanks, so the air reservoir tanks were relocated inside the carbody, and positioned vertically along side the steam generator. The batteries were relocated inside the carbody, and in the case of the A unit, they were placed beneath the cab floor, accessed by a louvered door. In the first production FA-2's this caused a restriction in airflow between the nose-mounted traction motor blower and the traction motors on the front truck. With great difficulty, this blower was moved into the engine room immediately behind the electrical equipment compartments. The carbody vent openings were covered with fine screen (chicken wire) on the intitial production units, but later production units incorporated Farr-Aire grills, which were superior in keeping rain and snow out of the engine room.