The SD45T-2 is a 6-axle diesel-electric locomotive built by EMD for the Southern Pacific Railroad. Like the later, SD40T-2 it is colloquially nicknamed a tunnel motor. 247 total units (including the original EMD/SP joint venture working Prototype) were produced from February 1972 to June 1975, including 84 for SP's subsidiary Cotton Belt. From April 1986 to December 1989, 126 were rebuilt and re-designated as SD45T-2R, including 24 for Cotton Belt.