GE "B23-7" and "BQ23-7" Locomotives: Specs, Roster, History

Last revised: January 1, 2025

The B23-7 was General Electric's first four-axle model of its new "Dash 7" line, which featured upgraded equipment and electronics.

As Brian Solomon notes in his book, "GE Locomotives," the B23-7 followed the earlier Universal line, GE's initial entry into the locomotive market as an independent manufacturer.

This particular model followed the U23B, a successful medium-horsepower, late era U-boat that saw 481 units completed at Erie.

The B23-7 continued this success and sold 545 units by the time production had ended in December, 1984. While EMD's SD40-2 line was unmatched during the 1970s, the "Dash 7" line would eventually help unseat Electro-Motive as the industry's top builder.

Today, you can still find the locomotive in active revenue service on smaller lines around the country, many of which have been rebuilt and upgraded over the years. Today, there is currently one known B23-7 preserved; Conrail #1943 found at the Conway Scenic Railway.

Photos

CSX BQ23-7 #3008 was photographed here by Wade Massie at Russell, Kentucky on August 8, 1991. Built for Seaboard Coast Line the "Q" designated "Quarters" and the model was identical to the B23-7 save for the larger cab. An experimental design, the SCL was attempting to save money by removing the caboose and placing the entire crew at the head end. The original 10 were the only units ever built.

History

The B23-7 was quite similar to its earlier cousin, the U23B. As Greg McDonnell notes in his book, "Locomotives: The Modern Diesel & Electric Reference, Second Edition," its notable external differences was:

An increase in length by 2 feet.

Larger Radiators.

Removal of the two additional side windows which bracketed the main cab window. Brian Solomon notes in his book, "GE And EMD Locomotives," the introduction of more expensive Lexan shatterproof glass made railroads weary of spending the extra money on the extra panes.

A slightly wider hood from just ahead of the exhaust stack to the radiator cab, which housed the relocated oil cooler. This "notch" is the easiest way to identify the "Dash 7" line over the earlier U-boat.

Other improvements not noticeable were largely internal and included:

Better fuel efficiency (a 16% improvement during the "Dash 7" line's production run).

Increased tractive effort.

A more reliable locomotive.

A better engine muffler to reduce noise, emissions, and improve fuel economy.

Implementation of the standard AAR "Notch 8" throttle (also referred to as the "skip three, double seven"). GE had previously used a sixteen notch throttle on earlier U-boats, which intended to offer engineers better speed control.

The introduction of the "Dash 7" line brought with it new model designations and meanings behind the numbers and letters. In regards to the B23-7:

"B" referred to a four-axle (B-B) locomotive.

"23" designated the horsepower rating (in this case 2,250 horsepower was available at the traction motors).

"7" indicated the "Dash 7" line was introduced in 1976.

The B23-7 used an updated version of GE's traction motor, the model 752AF; this enabled the road-switcher to boast 70,000 pounds of starting effort and 63,250 pounds of continuous effort at 10.7 mph.

Ferrocarriles Nacionales de México (NdeM) B23-7 #10018 on display at Railfair '81 in Sacramento, California on May 5, 1981. American-Rails.com collection.

For domestic lines there many buyers including Conrail (141), Missouri Pacific (85), Santa Fe (69), Louisville & Nashville (15), Providence & Worcester (1), Seaboard Coast Line (39, including 10 of the unique "BQ23-7" variant), Southern Pacific (15), Southern Railway (54), and Texas Utilities (2).

Additionally, Mexican lines Ferrocarriles Nacionales de México and Ferrocarriles Unidos del Sureste purchased 122 and 3 respectively.

Conrail B23-7 #1978, missing a number board, leads a string of boxcars in Ohio during May of 1982. American-Rails.com collection.

BQ23-7

Of note is another 10 purchased by the Seaboard Coast Line known as the BQ23-7. The "Q" designated "Quarters" and the model was identical to the B23-7 save for the larger cab.

Basically an experimental design, the SCL was attempting to save money by removing the caboose from the end of the train and placing the entire crew in the lead locomotive.

Santa Fe B23-7 #6351 in service at Turner, Kansas on June 21, 1985. American-Rails.com collection.

The idea did not work quite as well as the railroad had hoped and no more were built. The BQ23-7s remained in service on CSX through the 1990s until they were finally retired.

Taking what it had learned through its Universal line, GE's "Dash 7" models proved much more reliable mechanically and electrically, even though the company still employed basic, boxy carbody designs.

Data Sheet

Entered Production	9/1977 (Conrail #2800)
Years Produced	9/1977 - 12/1984
GE Class	B23-7
Engine	7FDL12 (12 cylinder)
Engine Builder	General Electric
Horsepower	2250
RPM	1050
Length	62' 2"
Height (Top Of Rail To Top Of Cab)	15' 4"
Width	9' 11"
Weight	253,000 - 280,000 Lbs
Fuel Capacity	2,150 Gallons
Air Compressor	3CDC (Westinghouse)
Air Brake Schedule	26NL (Westinghouse)
Trucks	B-B
Truck Type	Floating Bolster FB2 (GE)
Truck Wheelbase	9' 4"
Wheel Size	40"
Traction Motors	752AF (4), GE
Traction Alternator	GTA11AC, GE
Auxiliary Generator	GY27, GE
MU (Multiple-Unit)	Yes
Dynamic Brakes	Yes
Gear Ratio	83:20
Tractive Effort/Starting	70,000 Lbs
Tractive Effort/Continuous	63,250 Lbs at 10.7 mph
Top Speed	70 mph

Production Roster

Owner	Road Number	Serial Number	Order Number	Completion Date	Quantity
Conrail	2800-2816	41609-41625	1410	9/1977-11/1977	17
Santa Fe	6350-6363	41673-41686	1449	4/1978-5/1978	14
Louisville & Nashville	5115-5129	41725-41739	1441	2/1978	15
Providence & Worcester	2201	41740	1454	3/1978	1
Missouri Pacific	2289-2298*	41772-41781	1417	1/1978	10
Seaboard Coast Line (Family Lines System)	5100-5114	41797-41811	1447	1/1978-2/1978	15
Conrail	1900-1939	41907-41946	1451	5/1978-6/1978	40
Seaboard Coast Line (Family Lines System)	5130-5139 (BQ23-7)**	41947-41956	1453	10/1978 - 1/1979	10
Southern Railway	3970-3979	41979-41988	1445	9/1978	10
Southern Railway	3980-3989	41989-41998	1491	1/1979	10
Conrail	1940-1966	42053-42079	1456	7/1978-9/1978	27
Seaboard Coast Line (Family Lines System)	5140-5153	42123-42136	1492	9/1978	14
Missouri Pacific	2299-2318*	42148-42167	1452	10/1978-11/1978	20
Conrail	1967-1991	42305-42329	1493	3/1979-4/1979	25
Santa Fe	6364-6389	42410-42435	1496	4/1979-6/1979	26
Texas Utilities	3306	42436	1406	8/1979	1
Conrail	1992-2023	42539-42570	1409	7/1979-9/1979	32
Ferrocarriles Unidos del Sureste	522-524	42623-42625	1408	12/1979	3
Ferrocarriles Nacionales de México	9130-9139	42626-42635	1407	12/1979-1/1980	10
Missouri Pacific	2319-2338*	42680-42699	1403-2	11/1979-12/1979	20
Santa Fe	6390-6404	42929-42943	1414	4/1980	15
Missouri Pacific	4650-4659	42944-42953	1416-2	4/1980	10
Southern Pacific	5100-5114	42979-42993	1421	6/1980	15
Missouri Pacific	4660-4669***	43021-43030	1422	6/1980	10
Southern Railway	3990-4009	43110-43129	1423	2/1981-3/1981	20
Texas Utilities	3307	43192	1413	10/1981	1
Ferrocarriles Nacionales de México	9140-9145	43250-43255	1472	8/1980-9/1980	6
Ferrocarriles Nacionales de México	9178-9180	43291-43293	1414	6/1981	3
Ferrocarriles Nacionales de México	12001-12006	43294-43299	1402	2/1982-3/1982	6
Ferrocarriles Nacionales de México	9146-9177	43328-43359	1478	11/1980-1/1981	32
Ferrocarriles Nacionales de México	1-01 thru 1-08	43360-43367	1479	1/1981-2/1981	8
Southern Railway	4010-4023	43368-43381	1492	3/1981-4/1981	14
Ferrocarriles Nacionales de México	10001-10013	43382-43394	1426	10/1980-2/1981	13
Ferrocarriles Nacionales de México	12007-12011	43395-43399	1402	4/1982-5/1982	5
Ferrocarriles Nacionales de México	10014-10032	43500-43518	1471	2/1981-6/1981	19
Ferrocarriles Nacionales de México	10033-10046	43519-43532	1474	11/1981-12/1981	14
Missouri Pacific	4670-4684	43533-43547	1473	4/1981-5/1981	15
Ferrocarriles Nacionales de México	10047-10052	43580-43585	1474	12/1981-1/1982	6
Santa Fe	6405-6418	44081-44094	1491	12/1984	14

* Later renumbered 4000-4049.

** The BQ23-7 was equipped with an extra large head-end cab to accommodate all five crewman. It was attempt to eliminate the caboose.

*** Missouri Pacific #4667-4669 was completed as the upgraded, 3,000 horsepower B30-7A. The units were externally identical to the B23-7.

Missouri Pacific B23-7 #4682 and GP38-2 #2060 at Austin, Texas; December 17, 1983. Mike Bledsoe photo. American-Rails.com collection.

FB2 Truck

For the first time ever, GE cataloged its floating bolster (FB2) truck as standard on the B23-7. However, some roads still opted for something different; Conrail used the old AAR Type-B's (General Steel Casting's swing bolster, drop-side equalizer) on their entire fleet and Santa Fe went with AAR's on 34 of its 69 B23-7's.

In addition, Southern Railway, whose B23-7's sported high short hoods as was common practice on the railroad, rode on GE's standard FB2.

Finally, Seaboard Coast Line had theirs equipped with EMD's Blomberg trucks for a much smoother ride. Interestingly, SCL used trade-in Blomberg's on all of its earlier U-boats as well.

Nearly half of Southern Pacific's fleet of B23-7's can be seen here at Commerce, Texas in the spring of 1983. The SP purchased a small group of 15 units (5100-5114) in 1980. Mike Bledsoe photo. American-Rails.com collection.

Sources

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

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.

McDonnell, Greg. Locomotives: The Modern Diesel & Electric Reference, 2nd Edition. Buffalo: Boston Mills Press/Firefly Books, 2015.

Solomon, Brian. American Diesel Locomotive, The. Osceola: MBI Publishing, 2000.

Solomon, Brian. GE and EMD Locomotives: The Illustrated History. Minneapolis: Voyageur Press, 2014.

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