The ALCO RS-1 was a 4-axle road switcherdiesel-electriclocomotive built by Alco-GE between 1941 and 1953 and the American Locomotive Company from 1953 to 1960. The Montreal Locomotive Works built three RS-1s in 1954. This model has the distinction of having the longest production run of any diesel locomotive for the North American market. The RS-1 was in production for 19 years from the first unit Rock Island #748 in March 1941 to the last unit National of Mexico #5663 in March 1960.
The hood unit configuration of the RS-1 pioneered the road switcher type of diesel locomotive, beginning the move away from the carbody units which were the standard design for road diesel locomotives before then. Most North American locomotives built since have followed this basic design. In 1940, the Rock Island Railroad approached ALCO about building a locomotive for both road and switching service.
The first thirteen production locomotives were requisitioned by the US Army, the five railroads affected had to wait while replacements were manufactured. The requisitioned RS-1s were remanufactured by ALCO into six axle RSD-1s for use on the Trans-Iranian Railway to supply the Soviet Union during World War Two.
Consumers Power (CPOX) 401 1951 built RS-1 #79350 former Rutland 401 spent her final years of service switching coal cars at Consumers Energy's Essexville, MI power plant on the Saginaw River the unit is now at the Saginaw Railway Museum.
Chicago, Rock Island & Pacific 745 (believed to be the oldest existing RS-1, and one of the replacements for the 13 taken by the U.S. Army) at the Louisiana Steam Train Association yard in Jefferson, LA