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PROTOTYPE HISTORY
What exactly does the “RS” mean? In short: Road Switcher. The RS-18 is equally
comfortable in the yard or on the mainline. Wait a minute, this sounds familiar. Did we
just copy the SW1200RS manual?
“In short: Road Switcher. The SW1200RS is equally comfortable in the yard or on
the mainline.”
- SW1200RS Manual
Alright, whoever did that is fired … again!
The MLW RS-18 was the successor to the 1,600hp 244-powered RS-10 which proved
to be somewhat unreliable. There were no such issues with the 1,800hp RS-18, with
its 12-cylinder model 251B diesel engine. It is widely considered to be MLW’s most
successful product from both an operational and a mechanical point of view.
Based on the Alco RS-11, the Canadian-specific RS-18 (which MLW designated DL-718)
was alike in most aspects externally and internally except for the notchless hood ends
(those indents where the number boards are on an RS-11).
Montreal Locomotive Works constructed 351 RS-18s between December 1956 and June
1968 for eight railways including Canadian National (225), Canadian Pacific (72),
Pacific Great Eastern (29), and 25 for numerous other railways. The RS-18 was available
in both “standard” and “lightweight” versions, which usually, but not always, rode on
standard 9’-4” wheelbase AAR type B trucks or special lightweight trucks respectively.
CN acquired examples of both (131 standard versus 94 lightweight units).
CANADIAN NATIONAL
Canadian National’s fleet of 225 units, numbered 3615-3893, was delivered between
December 1956 and August 1960, designated MR-18a to MR-18g. This included 30
units with 80-mph gearing and steam lines for passenger service. The last was retired in
1993 after nearly four decades of service.
One colourful aside took place in 1967 when CN rebuilt six RS-18s with a new auxiliary
HEP engine and extended length short hood for Tempo passenger service in southwestern
Ontario. These six units were designated MRE-18g and lasted into the early 80s.
CANADIAN PACIFIC
Canadian Pacific’s units, numbered 8729-8800, were assigned classes DRS-18a and
DRS-18b and were delivered between March 1957 and July 1958. All were equipped
with a steam trainline so that they could be partnered with a steam generator equipped
unit. Starting in 1980 CP began a major rebuild program at their Angus Shops in
Montreal to extend their useful lifespan another 10-15 years. Eventually all 69 remaining
locomotives were upgraded, gaining the designation RS-18u. Both the CN and CP
fleets mostly worked across Ontario, Quebec and the Maritimes, although CP’s units
occasionally worked west of Winnipeg.