Last revised: December 28, 2022
By: Adam Burns
The B23-7 was General Electric's first four-axle model
of its new "Dash 7" line, which featured upgraded equipment and
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.
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:
Other improvements not noticeable were largely internal and included:
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:
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.
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.
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.
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.
|Entered Production||9/1977 (Conrail #2800)|
|Years Produced||9/1977 - 12/1984|
|Engine||7FDL12 (12 cylinder)|
|Engine Builder||General Electric|
|Height (Top Of Rail To Top Of Cab)||15' 4"|
|Weight||253,000 - 280,000 Lbs|
|Fuel Capacity||2,150 Gallons|
|Air Compressor||3CDC (Westinghouse)|
|Air Brake Schedule||26NL (Westinghouse)|
|Truck Type||Floating Bolster FB2 (GE)|
|Truck Wheelbase||9' 4"|
|Traction Motors||752AF (4), GE|
|Traction Alternator||GTA11AC, GE|
|Auxiliary Generator||GY27, GE|
|Tractive Effort/Starting||70,000 Lbs|
|Tractive Effort/Continuous||63,250 Lbs at 10.7 mph|
|Top Speed||70 mph|
|Owner||Road Number||Serial Number||Order Number||Completion Date||Quantity|
|Louisville & Nashville||5115-5129||41725-41739||1441||2/1978||15|
|Providence & Worcester||2201||41740||1454||3/1978||1|
|Seaboard Coast Line (Family Lines System)||5100-5114||41797-41811||1447||1/1978-2/1978||15|
|Seaboard Coast Line (Family Lines System)||5130-5139 (BQ23-7)**||41947-41956||1453||10/1978 - 1/1979||10|
|Seaboard Coast Line (Family Lines System)||5140-5153||42123-42136||1492||9/1978||14|
|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|
|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|
|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|
|Ferrocarriles Nacionales de México||10047-10052||43580-43585||1474||12/1981-1/1982||6|
* 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.
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.