File:CP Rail No. 4744 at the Canadian Railway Museum (Exporail) - August 2008 - 02.jpg

English: CP Rail No. 4744 (MLW M640); Built 1971; Montreal Locomotive Works; Montreal QC.

This locomotive, the only representative of the M-640 model, is also the only locomotive originally equipped with an 18-cylinder 18-251F diesel engine. When it emerged from the factory in March 1971, its configuration was C-C, meaning that all six axles were motorized. Thanks to its 4000 horse-power, it was able to move its 167 tons at a maximum speed of 120 kilometres per hour. Assigned to unit coal trains between the Crowsnest area and Vancouver, British Columbia, it was transferred to Eastern Canada in the late 1970s. Its career might have run its course without any incident of note if the Canadian Pacific had not decided to work with Asea Brown Boveri (ABB) to test alternating current technology. In 1984, the locomotive was used as a technological test bench. Trucks were reconfigured as A-1-A, meaning that the central axle was no longer motorized, and four alternating current traction motors were installed on the outer axles.

Over the following years, CPR 4744 was subjected to intensive usage and a barrage of tests. On a trip between Montreal and Binghamton in 1992, it suffered an irremediable mechanical failure: its crankshaft broke, and no replacement part existed. After spending a few years on the disused site of the Angus Shops, it was finally transferred to the Museum in 1998. CPR 4744 led the way to the widespread adoption of alternating current by all North American locomotive manufacturers in the 1990s.