The following diesels were part of the Chessie System roster, but to date no plastic HO-scale example has been offered: TR3, TR4, GP39, SD18 and SD20-2.

A rare EMD B-truck diesel was Chessie's GP39 set of twenty, numbered 3900-3919 with C&O ownership.

According to the Wikipedia entry for the GP39, EMD produced only 23 examples between 1969 and 1970. The C&O took most of the GP39's made with its set of twenty, all were delivered in Enchantment Blue with Yellow trim. The other three GP39's built went to two different roads: KCC-Kennecott Cooper had a pair and ASAB-Atlanta & St. Andrews Bay owned one.

The EMD SD18 roster on the Chessie was 19 units, numbered 7300-7318, that C&O took delivery of in 1963. Of the group of 19 that went into the Chessie in 1972, only 7 emerged to become CSX power.

The Wikipedia entry for the SD18 states this six-axle diesel was built by EMD from 1960-1963 and original owners beyond C&O included: Bessemer & Lake Erie; Chicago & Illinois Midland; Duluth Missabe & Iron Range; Reserve Mining; plus exorted SD18 to Brazil and Korea. The total production of SD18's was 114 examples.

A total of five SD20-2 diesels were rosterd by the Chessie System. Carrying B&O ownership and roadnumbers 7700-7704, the SD20-2 diesels were not created by EMD. The SD20-2 was a B&O Cumberland Maryland Shops product made from B&O SD35s.