Special duty and tempo units
Two RS18s with a steam generator car hauled the passenger trains between Sydney and Truro (until they were replaced by Railiners 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 snowplough service.
n 1967, 6 RS18s (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 aluminium Tempo passenger coaches. 3860 is seen in the green and yellow livery, 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 units became 3150-3155 (MRE-18g) in mid 1968 and were then painted in a unique livery — orange with the upper cab white and a grey CN symbol on the long hood.
Two units (3151, 3153) lost their electrical generator equipment after wrecks and were reclassified MR-18g. The equipment was re-installed in two baggage cars that became EGUs 15300 and 15301. The MR-18gs powered Tempo trains with either another MRE-18g or EGUs 15300-15302. The short hood was rebuilt with only a few louvers and the roof vents were modified