SP-3100

Built by the General Electric Company, this 2500 HP diesel locomotive was one of 68 model U25B freight engines acquired by the Southern Pacific in 1963. It became something of a celebrity in 1975 when it was repainted as Southern Pacific's Bicentennial engine in celebration of the nation's 200th birthday. It was retired in 1987 and purchased by the Museum the following year from the scrap dealer who had bought it from SP. The locomotive is part of our large collection of rail equipment from the Southern Pacific Railway and is used regularly to power trains on the Museum Railway. It was repainted in late 2010, and is the only operating example of the U-25B preserved anywhere.

The U25B (nicknamed U-Boat) put General Electric on the road to becoming the top locomotive producer in the U.S., a field that had been dominated for some time by EMD. Part of GE's "Universal" line of locomotives, it introduced many innovations to the U.S. diesel locomotive market, including a pressurized car body and a centralized air processing system that provided filtered air to the engine and electrical cabinet, thus reducing maintenance. The U25B was also the highest-horsepower four-axle diesel road locomotive in the U.S. at the time of its introduction, its contemporaries being the EMD GP20 (2000 hp) and the Also RS-27 (2400 hp).

In 1975, Southern Pacific rebuilt this locomotive and one other U25B at its Sacramento Shops with EMD electrical equipment, reclassifying them as U25BE's. The experiment was not considered successful and no other U25's were similarly converted.

Re-numberings: Originally numbered as SP 7508, re-numbered SP 6800 as part of 1975 rebuilding, re-numbered 3100 in 1979.

http://espee.railfan.net/spu25b.html

http://www.american-rails.com/ge-u25b.html