The ALCO HH series were an early series of switcher diesel-electric locomotives built by the American Locomotive Company (ALCO) of Schenectady, New York, between 1931 and 1940, when they were replaced by the S series; the 660 hp (490 kW) S-1 and 1,000 hp S-2. They were ALCO's first diesel switchers to enter true series production, and among the very first land vehicles anywhere to utilise the revolutionary diesel-electric power transmission. The "HH" name stood for "High Hood", a name ALCO came eventually to use in an official context, but originally an unofficial name. Model designations such as HH600 are only semi-official. Original ALCO designations were either descriptive or based on the internal order/design number. A total of 177 of the HH series were produced; this comprised one prototype and four production models of varying power outputs.
Recently selected: Lynton and Barnstaple Railway - Forth Bridge - Bourbonnais train accident