EMD "SD45" Locomotives

Last revised: March 24, 2023

By: Adam Burns

The EMD SD45 series included several variants of the original design, just had been the case with the SD40 series.

The model was manufactured from the mid-1960s through the mid-1970s and included such variants as the SD45-2, SDP45, SD45X, and SD45T-2.

The series was very successful, particularly the original model which sold more than 1,200 examples by itself. While EMD now built its locomotives using a standard frame and design (beginning with the SD35), the SD45 is easily distinguishable from its siblings by its rear flared radiator, a trademark that no other model featured.

However, perhaps it was the SD45 that in some ways began to show "cracks" in Electro-Motive's armor.

For the first time in the company's history a model it cataloged had some reliability issues. These were eventually resolved but it was a foreboding of things to come. 

In any event, the SD45 could pull almost anything and today, numerous units remain in revenue service on shortlines and regionals.


A handsome Santa Fe SD45-2, #5700, shows off its Bicentennial livery in Kansas City on February 26, 1975. J. Primm photo. American-Rails.com collection.


The EMD SD45 began production in late 1965 using General Motors' new 20-cylinder model 645E3 prime mover.

The SD45's 20-cylinders meant it was extremely powerful, able to produce 3,600 horsepower (600 horsepower more than the SD40 series released a year later), which was a significant reason so many railroads purchased the model.

Using GM's model D77 traction motors the SD45 could produce over 82,000 pounds of continuous tractive effort and 92,000 pounds starting, which was on par with what the SD38s could produce and the later SD40s.

Sales for the SD45 took off rather quickly given EMD's stellar reputation as a locomotive builder through the mid-1960s. However, as railroads began to use the locomotive they began experiencing reliability issues.

The 20-cylinder prime mover was experiencing teething issues and had a tendency to break crankshafts, naturally resulting in engine failures out on the road.

While EMD soon fixed the problem by replacing the main engine block with a new design many railroads were turned off of the locomotive after its initial problems and with the highly successful and reliable SD40 released in 1966 decided to just buy that model instead.

Rio Grande SD45 #5323 leads a freight through heavy snow just west of Loma, Colorado during the late 1960s. American-Rails.com collection.

In any event, the power the SD45 offered could not be denied and some lines truly liked theirs.

In 1967 EMD released the SDP45, which at 70-feet was five feet longer than the SD45. It was built for use in passenger service featuring a steam generator and water supply.

In this Great Northern publicity photo, new SDP45 #333 leads the "Empire Builder" in its redesigned "Big Sky Blue" livery near Montana's Glacier National Park during the fall of 1967. Author's collection.

Just 52 SDP45s were built for the Southern Pacific, Great Northern, and Erie Lackawanna (the EL purchased the most, 34).   In the summer of 1970 EMD began construction on the experimental SD45X.

The locomotive was rated at 4,200 horsepower and only the Southern Pacific purchased the model (3) with EMD owning 4 demonstrator units.

As with the SD40 series, in the spring of 1972 EMD released the upgraded SD45-2 model, which was virtually identical to its predecessor save for updated electronics allowing for the locomotive to be more efficient.

The model was built through 1974 with 136 units sold. Around the same time EMD also manufactured the SD45T-2.

A Northern Pacific publicity photo featuring four new SD45's just delivered from Electro-Motive at the Mississippi Street Shops in St. Paul, Minnesota in July, 1966. Author's collection.

As with the SD40T-2, requested by the Rio Grande, the SD45T-2 redesigned its air intakes to the locomotive's walkways and the radiators were moved as high as possible.

This allowed the locomotive to receive the clean, cool air found near the floor of tunnels (where exhaust and heat was an issue) and blowing it up through the radiators and out the top.

Erie Lackawanna SD45 #3633 is stopped with a westbound freight at the small depot in Deposit, New York during a crew change in March, 1970. Photographer unknown. Author's collection.

It proved to be an innovative and successful design as both the SD40T-2 and SD45T-2 sold quite well for a variant; the former selling more than 300 examples and the latter nearly 250, all of which went to the Southern Pacific/Cotton Belt (9157-9404).

Today, most of these units are in operation while SP #9193 is preserved at the California State Railroad Museum in Sacramento.

Data Sheet and Specifications

Entered Production12/1965 (Demonstrator #4351)
Years Produced (SD45)12/1965 - 12/1971
Years Produced (SDP45)5/1967 - 8/1970
Years Produced (SD45X)6/1970 - 2/1971
Years Produced (SD45-2)5/1972 - 9/1974
Engine (SD45X)645F3B
Engine BuilderGM
Horsepower (SD45X)4200
Cylinders (SD45X)16
Length65' 9 ½"
Length (SD45X)70' 8"
Height (Top Of Rail To Top Of Engine Hood)15' 2 13/32"
Weight368,000 Lbs
Fuel Capacity3200 Gallons
Fuel Capacity (SD45X)4400 Gallons
Air CompressorGardner-Denver
Air Compressor ModelWBO
Air Brake ManufacturerWestinghouse
Air Brake Schedule26L
Truck TypeFlexicoil
Truck Type (SD45X)HT-C
Truck Wheelbase13' 7"
Wheel Size40"
Traction MotorsD77 (6), GM
Primary GeneratorAR10, GM
Steam Generator (SDP45)Vapor-Clarkson (Model AR4125)
Auxiliary GeneratorDelco (A8102)
MU (Multiple-Unit)Yes
Dynamic BrakesYes
Gear Ratio62:15
Gear Ratio (SDP45)59:15
Tractive Effort (Starting)92,000 Lbs at 25%
Tractive Effort (Starting)89,500 Lbs at 25% (SDP45)
Tractive Effort (Continuous)82,100 Lbs at 11 mph
Tractive Effort (Continuous)82,100 Lbs at 6.6 mph (SDP45)
Top Speed65 mph
Top Speed (SDP45)95 mph
70021348726354234y235627968307098.jpgA pair of Frisco SD45's, along with GP35 #701, at Springfield, Missouri, circa 1970. Mac Owen photo. American-Rails.com collection.

Production Rosters


Owner Road Number(s) Quantity Date Built
Atlantic Coast Line1024-1033101966
Burlington Northern6472-6567961970-1971
Chicago & North Western901-920, 937-977611967-1969
Colorado & Southern Railway (BN)868-87471971
Delaware & Hudson801-80331966
Denver & Rio Grande Western5315-5340261967-1968
Electro-Motive (Demo)4351-435441965-1966
Erie Lackawanna3601-3634341967-1968
Great Northern400-426271966-1968
Illinois Central700011965
Milwaukee Road4000-4009101968
Norfolk & Western1700-18141151966-1969
Northern Pacific3600-3629301966-1968
Penn Central6235-623951968
Santa Fe1800-1889, 5590-56241251966-1970
Seaboard Coast Line2010-2044351968-1971
Southern Pacific8800-8963, 8982-9051, 9069-91513171966-1970
Southern Railway3100-3169, 3120 (2nd)711967-1970
St. Louis San Francisco Railway (Frisco)900-948491966-1969
St. Louis Southwestern Railway (Cotton Belt/SP)8964-8981, 9052-9068, 9152-9155391968-1970
Union Pacific3600-3649501968


Owner Road Number(s) Quantity Date Built
Clinchfield Railroad3607-3624181972-1974
Erie Lackawanna3669-3681131972
Santa Fe5625-5714901972-1974
Seaboard Coast Line2045-2059151974


Owner Road Number(s) Quantity Date Built
Southern Pacific9166-9260, 9302-9313, 9344-93701341972-1975
St. Louis Southwestern Railway (Cotton Belt/SP)9157-9165, 9261-9301, 9315-9343, 9371-94041131972-1975


Owner Road Number(s) Quantity Date Built
Erie Lackawanna3635-3668341969-1970
Great Northern326-33381967
Southern Pacific3200-3209101967


Owner Road Number(s) Quantity Date Built
Electro-Motive (Demo)5740, 4201-420331970-1971
Southern Pacific9500-950561970-1971

One of the Santa Fe's interesting SD45B's, #5501, was photographed here in Riverdale, Illinois on August 28, 1990. John Eagan, Jr. photo. Author's collection.

While not as successful as the SD40 series the EMD SD45 and its variants still sold very with more than 1,700 purchased by the time production had finally ended in the early summer of 1975.

After EMD corrected the model's engine block flaws most of the fleet remains in active revenue service today.

Other examples of the locomotive officially preserved include Erie Lackawanna #3607 at the National Museum of Transportation in St. Louis, Great Northern #400 ("Hustle Muscle") at the Lake Superior Museum of Transportation, Norfolk & Western #1776 at the Virginia Museum of Transportation, SP #8800 at the Utah State Railroad Museum, and EL SDP45 #3639 also at VMT. 

235920358273472352783689289078.jpgMilwaukee Road SD45 #4000 was photographed here at the company's terminal in Bensenville, Illinois in February, 1969. American-Rails.com collection.


  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.
  • Marre, Louis A. Diesel Locomotives: The First 50 Years, A Guide To Diesels Built Before 1972.  Milwaukee: Kalmbach Publishing Company, 1995.
  • Pinkepank, Jerry A. Diesel Spotter's Guide.  Milwaukee: Kalmbach Publishing Company, 1967.
  • Schafer, Mike. Vintage Diesel Locomotives. Osceola: MBI Publishing, 1998.
  • Solomon, Brian. American Diesel Locomotive, The. Osceola: MBI Publishing, 2000.
  • Solomon, Brian.  EMD Locomotives.  Minneapolis: MBI Publishing Company, 2006.
  • Solomon, Brian.  GE and EMD Locomotives:  The Illustrated History.  Minneapolis:  Voyageur Press, 2014.
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