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GE's "B40-8" and "B40-8W" Series, A Late Four-Axle Model

Last revised: February 11, 2024

By: Adam Burns

The B40-8 and B40-8W (also known as the Dash 8-40B/W) was the single, most powerful four-axle design General Electric cataloged.  It was also the company's last.

Built during the late 1980s, the model came in two versions using either the common Standard Cab or the newer, "North American Safety Cab."  

By the early 1990s the wide cab became a required feature on new locomotives, mandated by the Federal Railroad Administration to increase crew protection in the even of a collision.

While sales for the 8-40B and Dash 8-40BW saw more than 230 units roll out of Erie during the late 1980s and early 1990s.  Today, one can still find several examples operating on BNSF (B40-8Ws).

However, their time on the Class I is likely short; they have been in service for 30 years now and have not been extensively rebuilt. 

Interestingly, the wide cab variants did make it into the BNSF livery.  In addition, you can still catch examples on short lines and regionals.  


1oi91908ixmnbtc19819176510.jpgDuring the Santa Fe's late era the company elected to revived its classic Warbonnet livery. Here, four new Santa Fe B40-8W's show off the legendary paint scheme during October of 1990. Warren Calloway photo.


The B40-8, otherwise referred to as the Dash 8-40B, was merely an uprated B39-8, one of General Electric's original prototype "Dash 8s" released in 1984.

As Brian Solomon notes in his book, "GE Locomotives," the B40-8 coincided with GE's latest "Dash" series, a somewhat confusing moniker meant to differentiate later Dash 8 models from the original "Classics."

To further add to the confusion, the company at first referred to its cataloged locomotives as "Enhanced" variants before changing this to the "Dash" series.

In any event, there were some internal improvements (such as microprocessor upgrades and enhancements to the 7FDL16 prime mover) but most changes were to the carbody; the prototypes had utilized a chassis with long hood very similar to the Dash 7s and redesigned cab while production Dash 8s featured a more streamlined layout.

The noteworthy differences here included a Standard Cab that was a flush with the roofline, a lower nose, equipment blower and dynamic brakes that seamlessly melded into the carbody, and angled radiator vents.

By the late 1980s both GE and Electro-Motive were having a difficult time finding a market for high-horsepower, four-motored locomotives (EMD's GP59 and GP60 models, for example, sold just over 400 examples combined).

These designs, of course, had been a mainstay of main line power from the late 1930s until EMD successfully demonstrated the advantages of six-motored models in the 1960s.

But there still remained a market for four-motored road-switchers into the 1980s, predominantly in high-speed freight service where six-axles were unnecessary.  As a result, models like the Dash 8-40B continued to see some success. 

As Greg McDonnell notes in his book, "Locomotives: The Modern Diesel & Electric Reference, 2nd Edition," sales for four-axle road-switchers dried up simply due to the increased weight of trains.

Data Sheet

Entered Production4/1988 (Conrail #5060)
Years Produced4/1988 - 12/1991
GE ClassB40-8, Dash 8-40B, Dash 8-40BW
Engine7FDL16 (16 cylinder)
Engine BuilderGeneral Electric
Length (B32-8, Dash 8-32B)63' 7"
Height (Top Of Rail To Top Of Cab)15' 4 1/2"
Width9' 11"
Weight288,000 - 289,000 Lbs
Fuel Capacity3,150 Gallons
Air Compressor3CDC (Westinghouse)
Air Brake Schedule26L (Westinghouse)
Truck TypeFloating Bolster FB2 (GE)
Truck Wheelbase9' 0"
Wheel Size40"
Traction Motors752AG (4), GE
Traction AlternatorGMG186, GE
Auxiliary GeneratorGY27, GE
MU (Multiple-Unit)Yes
Dynamic BrakesYes
Gear Ratio83:20
Tractive Effort/Starting70,000 Lbs
Tractive Effort/Continuous68,000 Lbs at 18.3 mph
Top Speed70 mph

Production Rosters


Owner Road Number Serial Number Order Number Completion Date Quantity
Santa Fe7410-742945656-4567514126/198820
New York, Susquehanna & Western4002-4008 (Evens)45676-4567914156/19884
St. Louis Southwestern (Southern Pacific)8040-807445688-4572214147/1988-11/198835
Santa Fe7430-744945931-4595014164/198920
New York, Susquehanna & Western4010-4048 (Evens)45951-4597014174/198920
St. Louis Southwestern (Southern Pacific)8075-809445971-4599014185/198925
U.S. Department Of Energy (Savannah River Site)1074611514205/19891


Owner Road Number Serial Number Order Number Completion Date Quantity
General Electric (Demonstrator)809*429991301-119881
Santa Fe500-55946404-46463142210/1990-11/199060
Santa Fe560-58246906-4692814313/199223

* The original Dash 8 prototype, original numbered 606 and built in 1982.  Upgraded to 3,900 horsepower in 1986 and sported the original "North American" wide cab in 1989.  Never sold.


  • 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.

2969812798076138.jpgA quartet of Santa Fe B40-8W's lead trailers west over the Transcon main line at Hodge, California on the evening of September 12, 1993. American-Rails.com collection.

By the 1980s, outside of some perishable and auto part business, expedited railroad service had largely been relegated to intermodal double-stacks.  These trains were very heavy and four-motored locomotives simply could not handle such weights at the speeds required. 

As a result, the industry moved away from such designs permanently in favor of their six-motored counterparts.  Since the early 1990s, neither EMD or GE has offered a four-motored locomotive.

General Electric built just 155 B40-8s for Conrail, Santa Fe, St. Louis Southwestern and the New York, Susquehanna & Western.  In addition, the Department of Energy purchased a single unit.

The model was also the first to feature GE's new North American Safety Cab, a now-standard wide cab design.  The Santa Fe acquired 83 examples in the early 1990s and these units regularly handled fast freights across the West.

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