In early 1978, the Southern Pacific Railroad took delivery of four former SP U25B diesels that had been rebuilt by Morrison-Knudson with Swiss-made Sulzer V12 diesel engines. These four engines also featured external changes to the car bodies as well, and rather than dubbing them something like "U25BRs," they were given the model TE70-4S, along with a bright new red and orange paint job designed by Chester Mack (who also designed SP’s Bicentennial diesel scheme). As "semi demonstrators," M-K and Sulzer absorbed much, if not all, of the cost of these remanufactured units. All four of these, SP 7030-7033, were taken out of service in 1980 and 1981, and eventually scrapped in 1995. Late in its service life, on May 3, 1981, SP TE70-4S 7033 was found in the SP's Roseville, California, yard.