An EMD MP15T is a 4-axle diesel

Diesel locomotive

A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...

 switcher

Switcher

A switcher or shunter is a small railroad locomotive intended not for moving trains over long distances but rather for assembling trains ready for a road locomotive to take over, disassembling a train that has been...

 locomotive built by General Motors Electro-Motive Division between October 1984 and November 1987. This unit is basically a turbocharged version of the MP15AC.

42 examples of this locomotive model were built for the Seaboard System Railroad

Seaboard System Railroad

The Seaboard System Railroad was a former Class I railroad created by merging the railroads of the Family Lines System. Although sharing common ownership, the railroads of the Family Lines System used different names when conducting business...

and one unit for Dow Chemical Company.

In 2010 Progress Rail Services, A Caterpillar Company, purchased one MP15T from CSX making CSX's total count 41.