Bronze Medal of Horsepower - MLW M-640
The Bronze Medal of Horsepower goes to the one-of-a-kind Montreal Locomotive Works M-640 diesel, numbered 4744 for the Canadian Pacific Railway. Equipped with a unique 18-cylinder 251F prime mover, the M-640 is considered to be the most powerful single-engined model in the history of the American Locomotive Company. Originally built with a C-C wheel arrangement and six General Electric direct current traction motors in 1971, No. 4744 was also converted with four Brown Boveri alternating current motors 13 years later. This creates an A1A-A1A wheel arrangement where the center axle of each truck is non-powered.
The 4,000-hp M-640 is known to be the first North American AC-traction diesel-electric locomotive, albeit rebuilt from its DC configuration. This was probably the inspiration for today’s DC-to-AC conversions of more recent diesels, a cost-effective method of modernizing railroad fleets. Although it was only built as a testbed, No. 4744 still survives on static display at the Canadian Railway Museum (known as Exporail) of Saint-Constant, Québec.
CP 4744 image property of Exporail
