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EMD "SD45" Locomotives

Last revised: February 7, 2024

By: Adam Burns

Electro-Motive was determined to win the horsepower race of the 1960s and cataloged its most powerful standard model in late 1965, the SD45. 

To achieve its goal, EMD increased the size of its new 645 power plant to 20 cylinders, which increased horsepower to 3,600.  Visually, the SD45 was unmistakable from any other La Grange product up until that time with its long frame and flared rear radiator air intakes.  The latter trait was not repeated on standard production models until the SD80MAC of 1995.

Initially, the SD45 was quite successful - and went on to sell more than 1,200 examples.  However, railroads soon realized the additional 600 horsepower was not worth the increased maintenance investment.

In addition, it was the first in EMD's line to suffer mechanical issues.  These problems were eventually addressed in the "Dash 2" variant although by then most railroads opted for the less powerful, but more reliable, SD40-2.   Ultimately, only 136 examples of the SD45-2 were produced.

Nevertheless, the SD45 could outpull almost any other locomotive then in service and was popular on western roads like the Southern Pacific, Santa Fe, and Great Northern.

Background

In an era when manufacturers and railroads believed evermore horsepower achieved the greatest level of operational efficiency, powerful models like the SD45, U36C, and C636 were cataloged by the industry's three major builders.

There were even one-off monstrosities like the U50/U50C, DDA40X, DD35/A, and C-855.  Ultimately, railroads realized the greater horsepower was not worth the increased maintenance investment.

In his book, "EMD Locomotives," author Brian Solomon notes that in late 1965 EMD advertised nine new models equipped with its latest engine offered in a range of horsepower ratings, sizes, and wheel arrangements.

The SD45 was the most powerful and entered EMD's catalog in December, 1965 with the unveiling of Demonstrator #4351.  The big locomotive was equipped with a 20-cylinder variant of the builder's new model 645E3 prime mover.

To accommodate the larger power plant, engineers lengthened EMD's standard frame for its six-axle models by five feet.  As Bob Hayden notes in his book, "Diesel Locomotives: Cyclopedia - Volume 2," instead of fabricating a special frame for the SD45, EMD simply made it standard for all six-axle models in the 645 line.

As a result, the less powerful SD38, SD39, and SD40 have short "porches" fore and aft.  Interestingly, these "porches" are even more pronounced on the SD40-2, which featured an even longer frame to accommodate the new HT-C truck. 

The SD45's signature feature was its flared rear radiator, which was required to provide the cooling necessary for the greater engine ouput.  Mr. Solomon notes the average cost for a new SD45, depending on options, was $290,000.

Success and Concern

Sales for the SD45 took off quickly thanks to EMD's stellar reputation. However, as the model spent time in service customers soon recognized issues with these powerful locomotives.

Most notable was the 20-cylinder prime mover, which began experiencing teething issues and had a tendency to break crankshafts.  This significant problem naturally resulted in engine failures while in service and sidelined the locomotives for an extended period.  In addition, railroads did not like the larger flared rear radiator. 

SD45-2

As part of EMD's latest "Dash 2" line released in January, 1972, the SD45-2 solved its predecessors problems.  In his book, "Locomotives: The Modern Diesel & Electric Reference," author Greg McDonnell notes that EMD boasted 40 refinements with its new line.

Its most notable was the upgraded electrical system which included transistors, printed circuit boards, and solid-state modular components which replaced a labyrinth of old relays, switches, and interlocks commonly been found on all previous models. 

The new computer system controlled everything from voltage regulation, battery charging and excitation and throttle response to wheel-slip control, dynamic brakes, and the locomotive's sanders.

Interestingly, the SD45-2 was the one "Dash 2" variant that actually differed visually from its pedecessor.  EMD eliminated the flared rear radiator air intakes, replacing it with the builder's common flush-mounted design - only larger to provide proper air-intake for the 20-cylinder engine.

Unfortunately, the "Dash 2" line did not see the same jump in sales as the SD40 series.  Its biggest issue appears to have been the increased maintenance and fuel appetite.  Railroads were quite happy with the slightly less powerful - and less maintenance intensive - SD40-2.  Ultimately, just 136 SD45-2s were sold.

SDP45

Cataloged in 1967, this variant was a dual-service design, which carried a steam generator for passenger assignments.  To do so required a frame five feet longer.  Only 54 were sold to Southern Pacific, Great Northern, and Erie Lackawanna.  

EL wound up with the most, 34 examples built between 1969-1970.  Ironically, the railroad did not order theirs for passenger service.  Instead, the longer frame allowed for a larger, 5,000-gallon fuel tank (enabling complete runs from New Jersey to Chicago without refueling) while the rear space intended for a steam generator contained concrete to increase tractive effort.

SD45T-2

The SD45T-2 was the original "Tunnel Motor" variant, requested by Southern Pacific for operation in the high Sierra-Nevada mountain range of Donner Pass to eliminate clean air-intake problems while operating through tunnels and snowsheds.

To correct the overheating issue, EMD redesigned the rear section by placing the air-intakes low along the walkways where they could acquire the coolest, cleanest air.  In addition, the radiators were moved to very top of the hood. 

Overall, the new design gave the locomotive a very box appearance at the rear.  No other railroads ordered the "Tunnel Motor" package; Southern Pacific wound up with 247 units, 166 of which were sublettered for subsidiary St. Louis Southwestern Railway.  In 1974, Southern Pacific returned to EMD for the less powerful SD40T-2, a model also purchased by the Rio Grande.

Data Sheet and Specifications

Production Rosters

SD45

Total Built = 1,260

Reused Serials

SD45-2

Total Built = 136

SDP45

Total Built = 52

SD45X

Total Built = 7

SD45X

Only seven of this variant were produced in 1970-1971.  It was an experimental design which tested EMD's new "Dash 2" upgrades and could produce 4,200 horsepower.  The model was also equipped with EMD's latest HT-C truck, which was a standard option on the SD40-2.

Photo Gallery

Sources

• 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.