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EMD's "SD9" Locomotives

Last revised: January 13, 2024

By: Adam Burns

The SD9, often nicknamed the "Cadillac" for the smooth ride its Flexicoil trucks provided, was the builder's second six-motored model.  It followed the early SD7, offering a slight increase in horsepower.

While the industry remained settled on four-axle power in general road service, the SD9 nevertheless saw higher sales than its predecessor.  This trend would continue as EMD cataloged increasingly more powerful six-axle models, which drew increasingly more interest.

Externally, there are few visual clues to differentiate the two models as they feature nearly identical carbodies.   One notable buyer of the SD9 was Southern Pacific. 

The company was eager to purchase the SD7 for its secondary lines, and wound up with the largest fleet.  The railroad was so pleased with the model it also amassed the largest roster of SD9s. 

In fact, SP went on to rebuild many SD7s and SD9s, and several were still in regular service when the railroad merged with Union Pacific in 1996.

Photos

0182417241724721481298523609260937.jpgA faded Norfolk & Western SD9 soldiers on in service, seen here switching the former Virginian yard in Mullens, West Virginia during October of 1980. Rob Kitchen photo.

History

The SD9 was part of Electro-Motive's so-called "9 Line" which included the F9, SD9, GP9, and E9 which all debuted in 1954.

Among the model's most notable improvements was its use of EMD's latest power plant, the 567C, which offered an additional 250 horsepower.  This engine, as Brian Solomon notes in his book, "Electro-Motive: E Units and F Units," was the most advanced in the series up until that time.

Its upgrades included a redesign of the engine crankcase to withstand a greater beating in daily service, replacement of water seals susceptible to leaking on older model 567s, and an improved cooling circuit.  

Baltimore & Ohio SD9 #1837 is seen here in Cumberland, Maryland during March, 1975. The unit was assigned to hump yard service during this time. American-Rails.com collection.

Reception

The Southern Pacific was one of the first railroads to take notice.  The "Special Duty" line blended increased tractive effort with a lighweight truck to provide exceptional performance on secondary branch lines.

The SP fielded many of these, especially in Oregon, which contained stiff grades.  It quickly tested and soon purchased a fleet of 43 SD7s.  They likewise purchased the most SD9s, buying 150 of the 471 produced domestically (another 44 were acquired by foreign lines).

While the 515 units paled in comparison to the more than 4,000 four-axle GP9s sold, railroads were beginning to take notice of EMD's six-axle line.   Many which had tested the SD7 also purchased the SD9. 

6010294812741625126462536769820708.jpgA handsome quartet of Southern Pacific SD9's in the "Black Widow" livery, led by #5472, have freight #805 on the San Joaquin Line, circa 1958. Gordon Glattenberg photo. American-Rails.com collection.

Spotting Features

There were few telltale differences between the SD7 and SD9.  In his book, "A Field Guide To Trains," author Gerald Foster the only notable clue is the marker lights.  On the former these are more inset along the tapered short hood while on the latter they were moved further outward.

Data Sheet and Specifications

Entered Production1/1954 (Milwaukee Road #2224)
Years Produced1/1954 - 6/1959
Engine567C
Engine BuilderGM
Horsepower1750
RPM835
Cylinders16
Length60' 8 ½"
Height (Top Of Rail To Top Of Cab)15' 0"
Width10'
Weight300,000-360,000 Lbs
Fuel Capacity1200 Gallons
Air CompressorGardner-Denver
Air Compressor ModelWBO
Air Brake ManufacturerWestinghouse
Air Brake Schedule6BL
TrucksC-C
Truck TypeFlexicoil
Truck Wheelbase13' 7"
Wheel Size40"
Traction MotorsD37 (6), GM
Primary GeneratorD12d, GM
Auxiliary GeneratorDelco
Steam Generator (Optional)Vapor-Clarkson (Model OK4625)
AlternatorD14
MU (Multiple-Unit)Yes
Dynamic BrakesYes
Gear Ratio62:15
Tractive Effort (Starting)90,800 Lbs at 25%
Tractive Effort (Continuous)75,000 Lbs at 9.3 mph
Top Speed65 mph

Production Roster

Total Built = 515

Owner Road Number(s) Serial Number(s) Order Number Completion Date
Milwaukee Road 2224-2237 18769-18782 5287 1/1954-2/1954
Chicago, Burlington & Quincy 325-344 18984-19003 5313 3/1954
Great Northern 573-578 19340-19345 5285 2/1954
Southern Pacific 5340-5371 19429-19460 5322 3/1954-5/1954
Chicago & North Western 1703-1707 19498-19502 5326 5/1954
Chicago & North Western 1708-1710 19503-19505 5338 5/1954
Chicago & North Western 1701-1702 19506-19507 5339 5/1954
Southern Pacific 5387-5417 19928-19958 5365 2/1955-4/1955
Southern Pacific 5418-5423 19983-19988 5365 4/1955
Reserve Mining Company 1220-1222 19989-19991 5389 6/1955
Soo Line (Wisconsin Central) 2381 20120 5375 12/1954
Baltimore & Ohio 765-766 20121-20122 5376 12/1954
Baltimore & Ohio 772 20123 5388 12/1954
Baltimore & Ohio 767-771 20124-20128 5376 12/1954
Southern Pacific 5424-5444 20202-20222 5365 4/1955-5/1955
Southern Pacific 5372-5386 20223-20237 5381 1/1955-2/1955
Central of Georgia Railway 202-207 20445-20450 5394 3/1955-6/1955
Baltimore & Ohio 773-774 20451-20452 5395 4/1955
Chicago, Burlington & Quincy 345-374 20555-20584 (5399 6/1955-10/1955
Electro-Motive (Demonstrator) 5591 (became Duluth, Missabe & Iron Range #110) 20655 6523 7/1955
Chicago & North Western 1721-1724 20687-20690 5405 10/1955-11/1955
Chicago & Illinois Midland 50-54 20691-20695 5406 11/1955
Atlanta & St Andrews Bay 503-504 21046-21047 5421 1/1956
Reserve Mining Company 1223 21066 5422 5/1956
Great Northern 579-583 21247-21251 5431 5/1956
Southern Pacific 5449-5493 21274-21318 5435 1/1956-5/1956
Duluth, Missabe & Iron Range 101-109 21727-21735 5456 3/1956-4/1956
Colorado & Southern 820-830 22403-22413 5482 12/1956-1/1957
Reserve Mining Company 1224 22417 5485 12/1956
Great Northern 584-589 22486-22491 5488 1/1957
Denver & Rio Grande Western 5305-5314 22808-22817 5507 7/1957
Duluth, Missabe & Iron Range 111-128 23099-23116 5525 1/1957-3/1957
Duluth, Missabe & Iron Range 129-130 23117-23118 5538 3/1957
Elgin, Joliet & Eastern 600-602 23120-23122 5526 3/1957
New York, Chicago & St Louis (Nickel Plate Road) 340-359 23155-23174 5532 3/1957-4/1957
Chicago, Burlington & Quincy 430-439 23609-23618 5547 9/1957-10/1957
Chicago, Burlington & Quincy 440-459 23619-23638 5549 8/1957-9/1957
Duluth, Missabe & Iron Range 131-157 23911-23937 5555 2/1958-4/1958
Atlanta & St Andrews Bay 505 24062 5562 4/1958
Great Northern 590-597 24092-24099 5564 4/1958
Great Northern 598-599 24100-24101 5577 4/1958
Pennsylvania 7600-7624 24167-24191 5567 11/1957-1/1958
Duluth, Missabe & Iron Range 158 24487 5555 4/1958
Colorado & Southern (Burlington) 831-835 25011-25015 5589 4/1959
Colorado & Southern (Burlington) 836-842 25156-25162 5589 4/1959
Duluth, Missabe & Iron Range 159-174 25259-25274 5600 4/1959-5/1959
Reserve Mining Company 1225 25436 5603 6/1959

Export

Owner Road Number(s) Serial Number(s) Order Number(s) Completion Date
Chile Exploration Company 901-903 21484-21486 701157-701159 3/1956
Chile Exploration Company 904-905 21562-21563 701186-701187 5/1956
Orinoco Mining Company (Venezuela) 1011-1014 21942-21945 701322-701325 5/1956
Orinoco Mining Company (Venezuela) 1015-1017 23400-23402 701495-701496 5/1957
Korean National Railroad 101-120 23481-23500 701530-701549 5/1957-7/1957
Korean National Railroad 121-129 23897-23905 701638-701646 10/1957
Orinoco Mining Company (Venezuela) 1018-1020 24574-24576 701763-701765 5/1958

Rio Grande SD9 #5309 was only a few months old when photographed here by Jackson Thode between assignments at the engine terminal in Provo, Utah in 1957. Author's collection.

In addition, when either model was equipped with dynamic brakes two additional cooling fans were located over the blister.  Buyers of the SD9 were lines one might expect, requiring greater tractive effort in tough environments; the Rio Grande, Missabe, Pennsylvania, Great Northern, and Chicago & Illinois Midland among others.

A number of foreign lines also purchased the model which included Orinoco Mining of Venezuela, Korean National Railroad, and the Chile Exploration Company.

926923942735627826892890273.jpgColorado & Southern (Burlington) SD9 #838 passes the depot and Purina grain elevator in Loveland, Colorado with southbound loads of limestone for the Great Western Sugar factory during the 1960s. Photographer unknown. American-Rails.com collection.

Sources

  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.
  • Hayden, Bob. Diesel Locomotives: Cyclopedia, Volume 2 (Model Railroader). Milwaukee: Kalmbach Publishing Company, 1980.
  • 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.
  • Solomon, Brian.  EMD Locomotives.  Minneapolis: MBI Publishing Company, 2006.

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