From Wikipedia, the free encyclopedia
Jump to: navigation, search
MILW U25B 5005.jpg
Type and origin
Power type Diesel-electric
Builder GE Transportation Systems
Model U25B
Build date April 1959 – February 1966
Total produced 478
 • AAR B-B
Gauge 4 ft 8 12 in (1,435 mm) standard gauge
Prime mover GE FDL-16
Transmission Diesel electric
Performance figures
Power output 2,500 hp (1,900 kW)
Disposition most scrapped, a few in preservation

The GE U25B was General Electric's first independent entry into the United States domestic Diesel-electric locomotive railroad market for heavy production road locomotives since 1936. From 1940 through 1953, GE participated in a design, production, and marketing consortium (Alco-GE) for diesel-electric locomotives with the American Locomotive Company. Starting in 1956 GE launched its Universal Series of diesel locomotives for the export market. The U25B was the first attempt at the domestic market since its termination of the consortium agreement with Alco.


The U25B (nicknamed U-Boat) was the first commercially successful domestic diesel electric road locomotive designed, built, and sold by General Electric after its split with the American Locomotive Company (Alco), a company dating back to the steam era. Along with Ingersoll-Rand, GE built the first viable American diesel-electric locomotive in 1928. GE had previously produced a number of prototype diesel switchers, in part with Alco. The GE Universal Series started production in 1956 and some 400 export locomotives were sold before the U25B was offered in the United States. The U25B was announced by General Electric as a domestic model on April 26, 1960.

The U-Boat put GE on the road to becoming the top locomotive producer in the U.S., much to the chagrin of EMD. 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 GP20 (2,000 hp) and the RS27 (2,400 hp or 1,800 kW).

Though many were produced and sold, the only remaining U25B locomotives are in museums, as many were retired or scrapped at the end of their service life by the end of the 1980s.


Four Southern Pacific U25Bs were rebuilt by Morrison-Knudsen with a Sulzer V-12 prime mover. These locomotives, designated M-K TE70-4S, operated from 1978–1987.[1]


Only one remains in operating condition. Southern Pacific 3100 is now on permanent exhibit at the Orange Empire Railway Museum in Perris, California. Built in 1963, this locomotive was first numbered SP 7508. Later numbered SP 6800, it became a goodwill ambassador for the railroad in 1976 when it was painted in an elaborate red, white, and blue color scheme in celebration of the nation's bicentennial; it was later renumbered and repainted in standard SP livery and was donated to the museum. The 3100 is fully certified to run on any of the nation's railroads and is frequently used as motive power for offsite work trains.

A second U25B locomotive is currently undergoing restoration efforts at the Illinois Railway Museum in Union, IL. Former Milwaukee Road engine number 5056 (built in 1965) is being both cosmetically and mechanically restored for operation on the museum grounds.

A third U25B locomotive is on display at the Western Pacific Railroad Museum in Portola, CA. Former Milwaukee Road engine number 5057 can be made operable. It was purchased by Cascade Rail Foundation to eventually be displayed at the South Cle Elum Rail Yard.

New York Central #2500 is on display at the Lake Shore Railway Historical Society museum in North East, Pennsylvania.

Conrail 2510 was to be preserved by The Great Northeastern Rail Road Foundation, but the plans fell through and the engine is sitting in rough shape, in Glenmont, NY. It is currently owned by the National Railway Historical Society. It was built as New York Central 2510 in May 1964.

New York, New Haven & Hartford #2525 has been preserved by the Railroad Museum of New England/Naugatuck Railroad of Thomaston, CT. It wears its original New Haven colors, however it is not currently operational.

Original owners[edit]

Railroad Quantity Numbers Notes
General Electric (XP-24 testbed) 2 751–752 Never sold, retained by GE
General Electric (demonstrator) 4 753–756 High short hood; to Frisco 804–807
4 2501–2504 to Union Pacific 633–636
5 51-55 to Frisco 812, 815, 814, 813, and 811.
Atchison, Topeka and Santa Fe Railway 16 1600–1615 renumbered 6600–6615
Chesapeake and Ohio Railway 38 2500–2537 renumbered 8100–8137
Chicago, Burlington and Quincy Railroad 6 100–105 to Burlington Northern 5424–5429
Chicago, Milwaukee, St. Paul and Pacific Railroad ("Milwaukee Road") 12 380–391 380 retired 1966; remainder renumbered 5000–5010; renumbered 5050–5060
Chicago, Rock Island and Pacific Railroad 39 200–238 225–238 to Maine Central Railroad 225–238
Erie Lackawanna Railroad 27 2501–2527 to Conrail 2570–2596
Great Northern Railway 24 2500–2523 to Burlington Northern 5400–5423
Louisville and Nashville Railroad 27 1600–1626
New York Central Railroad 70 2500–2569 to Penn Central 2500–2569; to Conrail 2500–2569
New York, New Haven and Hartford Railroad 26 2500–2525 to Penn Central 2660–2685; to Conrail 2660–2685
Norfolk and Western Railway 1 3515 renumbered 8138 (wreck replacement for Wabash unit)
Pennsylvania Railroad 59 2500–2548, 2649–2658 renumbered 2600–2658; to Penn Central 2600–2658; to Conrail 2600–2658
St. Louis – San Francisco Railway ("Frisco") 23 800–803, 808–810, 816-831 804–807, 811-815 ex GE. Numbers 800–807 were high short hood units in black and yellow scheme; The next set (808–815) were low short hood units in black and yellow. The last 16, 816-831, were low hoods and delivered in the orange and white scheme. To Burlington Northern 5210–5233.
Southern Pacific Company 68 7500–7567 renumbered 6700–6767
Union Pacific Railroad 12 625–632, 637–640 633–636 ex GE demonstrators 2501-2504. The only railroad, other than the Frisco, to have high short hood U25Bs.
Wabash Railroad 15 500–514 to Norfolk and Western 3516–3529; renumbered 8139–8152
Total 478


  1. ^ Lustig 2003, p. 23


  • Marre, Louis A. (1995). Diesel Locomotives: The First 50 Years: A Guide to Diesels Built Before 1972. Railroad Reference Series (Book 10). Waukesha, WI, USA: Kalmbach Publishing. ISBN 0890242585. 
  • Komanesky, John. "General Electric U25B Roster". Extra 2200 South. Retrieved January 27, 2005. 
  • Lustig, David (May 2003). "Whatever happened to SP's 'Popsicles'?". Trains. 63 (5): 23. ISSN 0041-0934. 
  • Pinkepank, Jerry A. (1973). The Second Diesel Spotter’s Guide. Milwaukee, WI: Kalmbach Publishing Company. ISBN 0-89024-026-4. 
  • "What's up with the U25B" pp 40-41 Trains Magazine August 1960.

External links[edit]