The MLW RS-18 was an 1800 hp (1340 kW) diesel-electric

Diesel-electric

Diesel-electric transmission or diesel-electric powertrain is used by a number of vehicle and ship types for providing locomotion.A diesel-electric transmission system includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors...

 locomotive built by Montreal Locomotive Works

Montreal Locomotive Works

Montreal Locomotive Works was a Canadian railway locomotive manufacturer which existed under several names from 1883–1985, producing both steam and diesel locomotives. For a number of years it was a subsidiary of the American Locomotive Company...

 between December 1956 and August 1968. It replaced the RS-10

MLW RS-10

The Montreal Locomotive Works RS-10 was a road switcher built for the Canadian market. It was essentially an ALCO RS-3 in a redesigned carbody. It retained the RS-3's 12-cylinder Alco 244 engine. MLW built 129 of these locomotives before the model was replaced by the MLW RS-18.-Original owners:...

 in MLW's catalogue, and production totalled 351 locomotives, to eight customers.

It was the Canadian version of the ALCO RS-11

ALCO RS-11

The ALCO RS-11 is a diesel-electric locomotive of the road switcher type rated at 1,800 hp , that rode on two-axle trucks, having a B-B wheel arrangement.-Development:...

, although MLW did manufacture the RS-11 for Ferrocarriles Nacionales de México

Ferrocarriles Nacionales de México

Ferrocarriles Nacionales de México, was Mexico's state owned railroad company from 1938 to 1998, and prior to 1938 a major railroad controlled by the government that linked Mexico City to the major cities of Nuevo Laredo and Ciudad Juárez on the U.S. border...

.

Canadian National Railway

Canadian National Railway

The Canadian National Railway Company is a Canadian Class I railway headquartered in Montreal, Quebec. CN's slogan is "North America's Railroad"....

, by far the largest buyer of the RS-18, continued to specify the long hood as the front. By contrast, while all of Canadian Pacific Railway

Canadian Pacific Railway

The Canadian Pacific Railway , formerly also known as CP Rail between 1968 and 1996, is a historic Canadian Class I railway founded in 1881 and now operated by Canadian Pacific Railway Limited, which began operations as legal owner in a corporate restructuring in 2001...

's RS-10s were long-hood-forward, all of their RS-18s were short-hood forward. All of CN and CP's locomotives were delivered with full-height short hoods, as were the first four Pacific Great Eastern Railway, and first Roberval and Saguenay Railway

Roberval and Saguenay Railway

The Roberval and Saguenay Railway is a small railway company, wholly owned by Rio Tinto Alcan. It carries raw materials in portions of northern Quebec province, Canada. With about of track in total, it touches on such spots as Chicoutimi and Arvida and connects to the Canadian National Railway....

 unit. The remaining production was for locomotives with a low short-hood, giving the train crew much better forward vision.

Original owners

Railway	Quantity	Road number	Notes
Canadian National Railway Canadian National Railway The Canadian National Railway Company is a Canadian Class I railway headquartered in Montreal, Quebec. CN's slogan is "North America's Railroad"....	225	3615–3745, 3830–3893, 3100–3129
Canadian Pacific Railway Canadian Pacific Railway The Canadian Pacific Railway , formerly also known as CP Rail between 1968 and 1996, is a historic Canadian Class I railway founded in 1881 and now operated by Canadian Pacific Railway Limited, which began operations as legal owner in a corporate restructuring in 2001...	72	8729–8800
Cartier Railway Cartier Railway The Cartier Railway is a privately owned railway that operates 260 miles of track in the Canadian province of Québec. It is operated by the Cartier Railway Company, a wholly owned subsidiary of Arcelor Mittal, formerly Québec Cartier Mining Company...	8	101–108
International Nickel Company of Canada	3	208-2 – 208-4
Pacific Great Eastern Railway	29	587–599, 614–626, 628–630	578–599 renumbered 601–613; to British Columbia Railway 601–630
Quebec Iron and Titanium QIT-Fer et Titane QIT-Fer et Titane is a Canadian mining company located in Quebec. The company operates an ilmenite mine at Lac Tio in northern Quebec, and in southern Quebec operates refining facilities that produce titanium dioxide, pig iron, steel, and other metal products...	1	6	Renumbered 16
Roberval and Saguenay Railway Roberval and Saguenay Railway The Roberval and Saguenay Railway is a small railway company, wholly owned by Rio Tinto Alcan. It carries raw materials in portions of northern Quebec province, Canada. With about of track in total, it touches on such spots as Chicoutimi and Arvida and connects to the Canadian National Railway....	2	24, 25
Wabush Lake Railway Wabush Lake Railway The Wabush Lake Railway is a Canadian short line railway operating in the province of Newfoundland and Labrador.Opened in 1963, the railway operates a line running between Labrador City, Labrador, and Wabush, where it interchanges with the Quebec North Shore and Labrador Railway.The Wabush Lake...  / Arnaud Railway	11	901–911
Totals	351