American Locomotive Co. / Montreal Locomotive Works
Montreal Locomotive Works (MLW) was founded in 1902 and was controlled by the American Locomotive Company (ALCO).
In 1949 MLW began to build ALCO-designed diesel locomotives under licence.
In the late 1960s, after ALCO had been purchased by the Worthington Corporation, MLW became MLW-Worthington. In 1969 MLW-Worthington purchased the engineering designs and world licences for the ALCO products.
In 1975 Bombardier purchased the majority interest in MLW-Worthington. In addition to designing the LRC passenger train (Light, Rapid and Comfortable) powered by 3,750 hp locomotives, Bombardier introduced an updated series of freight locomotives called the High Reliability (HR) series. In the model number the first digit (4 or 6) designated the number of axles on the locomotive and the second and third digits the number of cylinders in the engine. This gives the models HR412 and HR616 and these used similar engines to those in earlier models. The HR-412 carbody was similar to that of the M420 but the HR-616 had a new full width carbody and newly designed controls featuring many lighted rotary switches.
These HR-series locomotives were only purchased by CN and were scrapped or sold at about the same time as the older M-420 and C630M / M636 model that they were designed to replace.
Finally Bombardier discontinued locomotive manufacture in Canada although the company still maintains a global manufacturing business for rail-transportation vehicles. In 1988 Bombardier sold the former MLW factory to General Electric (Canada), which briefly used it to rebuild locomotives into the Super 7 series. GE closed the former MLW plant at the end of 1993.
S-7s, S-12s and S-13s did not operate west of Ontario, although a few late S-4s could be found in Western Canada during the 1950s. By the 1960s all CN ALCO and MLW switchers were restricted to operation in the Central and Atlantic Regions. Most of the S-2s, S-3s and S-4s formerly assigned to the Western Region were reassigned to Southern Ontario in the 1960s. The 8700 series worked mainly in Moncton,Halifax, and Saint John, N.B., and surrounding areas.