CN 3875 was an RS-18 built in 1960 by the Montreal Locomotive Works (MLW). CN classified it as class MR-18g.
I don't have a photo of CN 3875 but it was on a couple of train orders. It was on two detoured CN freights through Mattawamkeag, Maine (CPR line). The first recording I have was on May 1, 1973 with a westbound extra - CN 3875, CN 3843, CN 3687. Those engines returned at 23:05 on May 4, 1973 with CN 3875 leading and 3687 and 3843 trailing.
CN 3875 was rebuilt in 1975 in the RS-18 to RSC-14 conversion by replacing the B-B trucks with A1A trucks* and reducing the horsepower from 1800 to 1400. It was renumbered to CN 1774 and became part of class MR-14c. Here it is shortly after the rebuild in Dartmouth, Nova Scotia on May 31, 1976 (photo by Walter Matuch. Walter is the owner of Ready Made Trains).
Sometime between 1976 and 1984, CN 1774 was repainted and received the CN sergeant stripes. This slide by Glenn Courtney was shot in Halifax on October 13, 1984. Note sister CN 1782 behind her.
CN 1774 was retired before 1996 and presumably scrapped.
* B-B trucks are four wheel trucks, all powered. A1A trucks are six wheel trucks with the middle pair of wheels unpowered. The idea was to spread the weight of the locomotive over more wheels to allow them to operate on lighter branchline tracks.