ALCO HH series [SEP] manufacturer
ALCO HH series
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 S-1 and S-2. They were ALCO's first diesel switchers to enter true series production, and among the very first land vehicles anywhere to use 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.
ALCO 600 (New Haven #0900).
The first HH series locomotive, ALCO demonstrator #600 was mechanically almost identical to the others, but the appearance differed. The