AlCO

ALCO stands for the American Locomotive Company, a major American manufacturer of railroad locomotives and related equipment. Founded in 1901 through the consolidation of several locomotive builders, ALCO established its headquarters in Schenectady, New York, and grew to operate large plants across North America. It also extended its reach internationally through the Montreal Locomotive Works, its Canadian subsidiary, which built ALCO designs for the Canadian market.

During the steam era, ALCO produced a wide range of locomotives used by many railroads in the United States and Canada, including freight and passenger engines. In the postwar period, ALCO became a leading producer of diesel-electric locomotives. It introduced several notable models, including the FA and PA series for freight and passenger service, as well as switchers and road locomotives based on the company's advanced diesel designs. ALCO’s diesel program was supported by its 251 family of prime movers, and MLW in Canada produced or assembled ALCO designs for broader markets.

In the face of intense competition from Electro-Motive Division (EMD) and later other manufacturers, ALCO's fortunes declined in the 1960s and its locomotive production waned. The company eventually ceased locomotive production, and its assets and brands were dispersed over time. Today, many ALCO locomotives remain in operation on heritage railways or preserved in museums, forming an enduring part of North American railroad history.