MLW RS-18

{{one source|date=December 2014}}

{{Infobox locomotive

|name = MLW RS-18

|powertype = Diesel-electric

|image = BCRAIL 629 at Lillooet, BC (22420218258).jpg

|caption = BC Rail {{Abbr|No.|Number}} 629 at Lillooet, British Columbia in 1987

|builder = Montreal Locomotive Works

|ordernumber =

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|buildmodel = RS-18

|builddate = December 1956 to August 1968

|totalproduction = 351

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|aarwheels = B-B

|uicclass = Bo'Bo'

|gauge = {{track gauge|ussg|allk=on}}

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|primemover = ALCO 12-251B

|rpmrange = 1000 (max)

|enginetype=Four-stroke V12 diesel

|aspiration =

|displacement = {{convert|8016|cuin|L|abbr=on}}

|alternator =

|generator=DC generator

|tractionmotors= 4 DC traction motors

|cylindercount = 12

|cylindersize = {{convert|9|x|10.5|in|mm|0|abbr=on}}

|transmission=Electric

|multipleworking =

|maxspeed =

|poweroutput = {{convert|1800|hp|kW|-1|abbr=on}}

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| locobrakes=Air, optional dynamic

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| trainbrakes=Air

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|locale = Canada

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The MLW RS-18 was an {{convert|1800|hp|kW|sigfig=3|abbr=on}} diesel-electric locomotive built by Montreal Locomotive Works between December 1956 and August 1968. It replaced the RS-10 in MLW's catalogue, and production totalled 351 locomotives, to eight customers.

It was the Canadian version of the ALCO RS-11, although MLW did manufacture the RS-11 for Ferrocarriles Nacionales de México.

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