Missouri Pacific MP 4515, a GE U23B at Marion, IL, December 1988.

(Gary Todd from Xinzheng, China, CC0, via Wikimedia Commons)


GE Logo, black & white.


The GE U23B was a 2,250 horsepower diesel-electric locomotive built by GE Transportation from 1968 to 1977. It was one of the most successful models of the Universal Series, with 481 units built, including 16 exported to Peru. The U23B was replaced by the B23-7.



Featuring a 12 cylinder FDL engine, the U23B was a derivative of the U30B with a lower horsepower rating, producing 2,250 hp compared to the U30B's 3,000 hp.

A variant with 6 axles instead of 4 was produced, known as the U23C.


Nacionales de Mexico GE U23B 9117 at Pittsburgh, Pennsylvania, April 21, 1975. Photographer: David H Hamley.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/51720577056/)


NdeM power was pretty snazzy when it was freshly painted! Here is U23B 9117 being delivered, having just been built at GE at Erie, Pennsylvania. NdeM bought a single order for 30 units, 9100-9129, delivered between March and June, 1975. Another ten followed for Ferrocarril del Pacifico in August and September. All of the NdeM units had GE's FB-2 trucks, except seven units, 9114-9121, which had these rougher riding drop equalizer trucks, along with the FCP units. - Craig Garver.


Ferrocarril del Pacifico GE U23B 546 at Nogales, Sonora, Mexico, September 11, 1983. Photographer: Craig Garver.  El Costeno, "La Bala," has just completed it's run to Nogales from Guadalajara, and the power has already pulled off and headed for the roundhouse. FCP 546 has just taken the train around the wye and is readying the train for it's 5:00 p.m. departure later in the day. - Craig Garver.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/51752633089/

Ferrocarril del Pacifico GE U23B 542 at Nogales, Sonora, March 27, 1976. Photographer: Thomas Chenowith.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/51755896673/)

Original owners

Railroad Quantity Numbers Notes
Atchison, Topeka and Santa Fe Railway 49 6300-6348
Chesapeake and Ohio Railway 30 2300–2329 Blomberg trucks
Conrail 10 2789–2798
Delaware and Hudson Railway 16 301-316
Ferrocarril del Pacífico 10 537-546
Lehigh Valley Railroad 12 501-512 financed by USRA, to Conrail 2777–2788 in 1976
Louisville and Nashville Railroad 90 2708–2772, 2800–2824 FB-2 trucks
Milwaukee Road 5 4800-4804
Missouri-Kansas-Texas Railroad 3 350-352
Missouri Pacific Railroad 39 668-674, 2257–2288 FB-2 trucks
Monon Railroad 8 601-608 to L&N 2700–2707 in 1971
Ferrocarriles Nacionales de México 30 9100-9129 9114-9121 AAR type-B trucks, all others FB-2
Penn Central Transportation 77 2700–2776 to Conrail 2700–2776 in 1976
Southern Peru Copper 16 40-45, 50-59 FB-2 trucks
Southern Railway 70 3900-3969 High-nose, 3900–3914 with AAR type-B trucks, 3935–3969 with FB-2, all long hood forward
Texas Utilities 1 103
Western Pacific Railroad 15 2251–2265 Blomberg trucks

Conrail CR 2728 (U23B) at Danville, IL, November 1985.

(Gary Todd from Xinzheng, China, CC0, via Wikimedia Commons)


Surviving locomotives

Not many U23Bs still exist, but a few shortline and regional railroads still use them in everyday service. The Georgia Central Railway was one of the last U23B holdouts, rostering almost all of the remaining ex Southern Railway (U.S.) high short hood U23Bs. The Georgia Central as of July 2015 has all of its U23Bs off of the roster with the 3965 going to the Southern Appalachia Railway Museum in Oak Ridge, TN. Another U23B, CSX 9553, former L&N 2817, is preserved at the museum and is operable.

The Huntsville and Madison County Railroad Authority in Huntsville, AL, operates one of the last U23B's used in daily freight service, as of April 2020. HMCR 9554 was originally built in late 1974 as L&N 2800. The last U23B built, originally Conrail 2798, and more recently Providence and Worcester 2203, is in regular excursion service at the Naugatuck Railroad, operated by the Railroad Museum of New England in Thomaston, Connecticut.

Western Rail Inc in Airway Heights, WA currently has a U23B that is leased out to other railroads. It is numbered NIWX 2204 and is a Northern Illinois and Wisconsin locomotive. RJ Corman operates at least one, Road Number 2300, after acquiring the Lehigh Railway short line in Northeast Pennsylvania.


Delaware & Hudson GE U23B 2316 at Mechanicsville, New York, August 12, 1976. Photographer: J R Quinn.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/50343110546/)


GE U23B Overview

Type and origin
Power type: Diesel-electric
Builder: GE Transportation Systems
Model: U23B
Build date: August 1968 – June 1977
Total produced: 481
Configuration: AAR B-B
Gauge: 4 ft 8+1⁄2 in (1,435 mm)
Wheel diameter: 40 in (1,000 mm)
Length: 60 ft 2 in (18.34 m)
Width: 9 ft 11 in (3.02 m)
Height: 15 ft 4.5 in (4.69 m)
Locomotive weight: 242,000 lb (109,769 kg)
Prime mover: GE 7FDL-12
Cylinders: 12
Performance figures
Maximum speed: 70 mph (113 km/h)
Power output: 2,250 hp (1,680 kW)
Tractive effort: 90,000 lb (41,000 kg)


Western Pacific GE U23B 2251 at Oakland, California, April 7, 1976. Photographer: Vic Reyna.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/50377379611/)