Special duty and Tempo units
Two RS-18s with a steam generator car hauled the passenger trains between Sydney and Truro (until they were replaced by Railiners [Budd RDCs] in the mid-1970s) and Matapedia and Gaspe (until replaced by F units in the 1980s). Re-geared units were also used on passenger extra trains throughout Atlantic Canada and the Central Region when sufficient F units or Railiners were not available.
Several units were fitted with special covers to keep snow out of the radiators when the locomotives were used in snowplow service.
In 1967, six RS-18s (3850, 3883, 3860, 3856, 3884 and 3887) were rebuilt with a Cummins head-end-power unit (HEP) in the enlarged short hood for use with the aluminum-bodied Tempo passenger cars, and were classified MRE-18g. No. 3860 is seen in the temporary green-and-yellow livery, applied to all six RS-18M units after rebuilding, at Ottawa in January 1968. The enlarged short hood occupied the space where the end walkway would normally be located and had a unique layout of grilles (see photos) including two large horizontal openings near the top of the short hood on both sides and additional cooling vents on the roof. The intercooler is covered with chicken wire.
The Tempo units became Nos. 3150-3155 (MRE-18g) in mid-1968 and at that time were painted in a unique livery — red-orange with the upper cab light grey, and black roof and underbody.
Two RS-18M units (3151, 3153) lost their electrical generator equipment after accidents and were reclassified MR-18g. The HEP equipment was re-installed in two baggage cars that became Electrical Generating Units (EGU) Nos. 15300 and 15301. The MR-18gs powered Tempo trains with either another MRE-18g or EGUs 15300-15302. The short hoods of Nos. 3151 and 3153 were rebuilt with only a few louvers and the roof vents were modified.