EMD MP15T

The EMD MP15T was a diesel-electric switcher locomotive produced by General Motors Electro-Motive Division, with production running from October 1984 through November 1987. The model emerged as a variation within EMD's established MP15 family, which had been a reliable platform for yard and local freight service since the early 1970s. The MP15T represented a relatively specialized production run, with a total of 43 units constructed across its production life. The primary customer for the MP15T was the Seaboard System Railroad, which acquired 42 units numbered 1200 through 1241. When Seaboard System was merged into CSX Transportation, these locomotives passed to the new owner and retained their original road numbers. A single additional unit was purchased by Dow Chemical Company, numbered 957, making the MP15T among the more industrially distributed of EMD's switcher variants. In 2010, Progress Rail, a subsidiary of Caterpillar, acquired unit 1220 from CSX, reducing CSX's fleet to 40 examples. The MP15T occupies a modest but noteworthy place in the history of EMD's switcher development, representing one of the later production runs of the MP15 family before that line concluded. Its concentration among just two buyers made it a comparatively rare sight on North American railroads, and the subsequent ownership changes of the CSX fleet illustrated the active secondary market that existed for serviceable yard power during that era.

The MP15T was powered by a turbocharged 8-cylinder version of the EMD 645 engine, designated the 645E3, which distinguished it from other members of the MP15 family that typically employed mechanically aspirated 12-cylinder 645 engines. The application of turbocharging to a smaller displacement configuration allowed the locomotive to achieve a rated output of 1,500 horsepower, consistent with the broader MP15 line's power rating, while doing so through a different engineering approach. The locomotive rode on a B-B wheel arrangement, with two two-axle trucks, and employed direct current traction equipment in keeping with standard EMD switcher practice of the period. Despite the differences in its prime mover configuration, the external appearance of the MP15T closely followed that of other MP15 variants, preserving the family's characteristic hood-unit switcher profile. This design continuity meant the MP15T could easily be mistaken for its siblings without close inspection of its mechanical particulars, a common trait among EMD's incremental model variations during this period. The use of the turbocharged 8-cylinder 645E3 in a switcher application was a relatively uncommon configuration and contributed to the model's limited but distinct identity within the broader EMD locomotive catalog.