ALCO RS-1

The ALCO RS-1 was a four-axle diesel-electric road switcher built by Alco-GE from 1941 to 1953 and by the American Locomotive Company itself from 1953 to 1960, with Montreal Locomotive Works adding three more in 1954. It grew out of a 1940 request from the Rock Island Railroad for one machine that could handle both main-line and yard work. ALCO answered with a hood unit instead of the full-width carbody then usual, which gave the crew better visibility and let the locomotive run in reverse without being turned. Its nineteen years in production, from Rock Island number 748 in March 1941 to National of Mexico number 5663 in March 1960, were the longest run of any diesel built for the North American market. The first thirteen built were requisitioned by the United States Army and rebuilt as six-axle RSD-1 units for the Trans-Iranian Railway.