GE "U23C" Locomotives

Last revised: September 26, 2022

By: Adam Burns

The U23C, developed in the latter 1960s, was a late model U-boat manufactured by General Electric for use in yard, transfer, and heavy drag service.

It featured a variation of GE's 7FDL prime mover and was meant to compete with similar models offered by the Electro-Motive Division (EMD), notably the SD38 and SD39.

In this case, neither GE or EMD saw particularly strong sales; the SD38/SD38-2 series sold just 198 examples and the U23C saw just 53 domestic sales.

Ironically, GE's variant outsold EMD's thanks to a large order for Rede Ferroviária Federal, the Federal Railways Of Brazil, which acquired 170 examples alone.

The specialized nature of the U23C was not of particular interest to many by the late 1960s, especially considering that other models could perform the very same tasks, notably EMD's SD40 series or even the U30C.

Railroads that tended to buy the U23C were either strapped for cash (Penn Central) or merely testing the waters (GE products at the time tended to come with a lower price tag). 

Today, there is one U23C preserved Lake Superior & Ishpeming #2300 (in its original colors and number, the first U23C to roll out of Erie) located at the Arkansas Railroad Museum.  


Lake Superior & Ishpeming U23C #2300 (built new for the railroad in February, 1968) and a few other units are running eastbound through Negaunee, Michigan on January 3, 1983. Brian Rackley photo.

History And Background

The U23C began production in March, 1968 using a 12-cylinder version of the company's 4-cycle 7FDL prime mover, which could produce 2,250 horsepower.

The model was almost identical to the U30C save for six access doors in place of the standard eight found on most other U-boats equipped with the 7FDL16 prime mover.

GE's six axle Universal locomotives offered far greater tractive effort than their four axle counterparts.  The U23C featured ratings of 90,000 pounds of starting effort and 85,800 pounds while in motion at 7.3 mph.

The company cataloged the model as a slow-speed, heavy drag locomotive. As Brian Solomon notes in his book, "GE Locomotives," the Penn Central used their small fleet in yard service.

Santa Fe U23C #7514, an SD24, and a caboose rest for the holiday at Deming, New Mexico on January 1, 1981. The AT&SF purchased 20 examples of this model, #7500-7519. Doug Kroll photo.

The U23C was essentially a transfer locomotive, which other builders, like Baldwin and Alco had attempted to market more than a decade earlier. Once again many systems found little interest in this specialty locomotive type.

The U23C's sales appeared stronger due to the 170 units acquired by Brazil's Rede Ferroviária Federal.  Greg McDonnell points out in his book, "U-boats," its initial fleet of 20 units (3901-3920) was completed at Erie without trucks.

The locomotives were then transferred to GE's plant in Sao Paulo where Brazilian trucks and GE traction motors were applied.  The remaining 150 examples were all completed in Brazil.

The US railroads that purchased the U23C included the Santa Fe (20); Chicago, Burlington & Quincy (9), Lake Superior & Ishpeming (5), and Penn Central (19).

Data Sheet and Specifications

Entered Production3/1968 (Lake Superior & Ishpeming #2300)
Years Produced3/1968 - 9/1970
GE ClassU23C
Engine7FDL12 (12 cylinder)
Engine BuilderGeneral Electric
Length67' 3"
Height (Top Of Rail To Top Of Cab)15' 4"
Width10' 3 1/2"
Weight348,000 Lbs
Fuel Capacity2,900 Gallons
Air Compressor3CDC (Westinghouse)
Air Brake Schedule26L (Westinghouse)
Truck TypeTrimount/Adirondack
Truck Wheelbase13' 9"
Wheel Size40"
Traction Motors752 (6), GE
Traction GeneratorGT581, GE
Auxiliary GeneratorGY27, GE
MU (Multiple-Unit)Yes
Dynamic BrakesOptional
Gear Ratio74:18
Tractive Effort/Starting90,000 Lbs
Tractive Effort/Continuous85,800 Lbs at 7.3 mph
Top Speed70 mph

Production Roster

(Total Built = 223)

Owner Road Number Serial Number Order Number Completion Date Quantity
Lake Superior & Ishpeming2300-230136706-3670725003/1968-4/19682
Santa Fe7500-751937098-3711725156/1969-7/196920
Lake Superior & Ishpeming23023713825099/19691
Penn Central6700-671837540-37558252510/1970-11/197019
Lake Superior & Ishpeming2303-230437572-3757325099/19702
Rede Ferroviária Federal (Federal Railways Of Brazil)3801-38802500247-2500326-12/1972-8/197480
Rede Ferroviária Federal (Federal Railways Of Brazil)3901-39202500603-2500622-11/1975-1/197620
Rede Ferroviária Federal (Federal Railways Of Brazil)3921-39902500623-2500692-1974-197670


  • Marre, Louis A. and Pinkepank, Jerry A. Contemporary Diesel Spotter's Guide, The: A Comprehensive Reference Manual To Locomotives Since 1972.  Milwaukee: Kalmbach Publishing Company, 1989.

  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.

  • McDonnell, Greg. U-boats.  Toronto: Stoddart Publishing, 1994.

  • Solomon, Brian. GE Locomotives: 110 Years Of General Electric Motive Power. St. Paul: MBI Publishing, 2003.

A trio of Lake Superior & Ishpeming's U23C's, all acquired new by the railroad, is switching an ore train at Eagle Mills, Michigan in June of 1976. Rob Kitchen photo.

While the historic LS&I purchased the fewest, it found the locomotives well suited in heavy drag service hauling loads of iron ore through Wisconsin and Michigan's Upper Peninsula.

The company continued to use the six-axle locomotives through the 1990s before finally replacing them with newer motive power.

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