The Chessie System GP15T diesels were received from EMD in 1981. EMD's GP15 diesel was the company's answer to railroad's rebuilding their older geeps in the '70s. EMD offered the GP15-1 to roads on trade-in of an older geep. Chessie's 25 examples came with no motive trade between the road and EMD, which was unique in GP15-1 situations. Additionally, Chessie's examples were turbocharged and labeled GP15T. The GP15-1 was not turbocharged. Chessie System GP15's are also rare among others, as they have dynamic braking.

The recent HO-scale GP15 models from Proto 1000 and Athearn Genesis have ignored the Chessie GP15T to date.