EMD "SD9" Locomotives: Data Sheet, Specs, Roster

Last revised: December 17, 2024

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

A 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.

A 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 Production	1/1954 (Milwaukee Road #2224)
Years Produced	1/1954 - 6/1959
Engine	567C
Engine Builder	GM
Horsepower	1750
RPM	835
Cylinders	16
Length	60' 8 ½"
Height (Top Of Rail To Top Of Cab)	15' 0"
Width	10'
Weight	300,000-360,000 Lbs
Fuel Capacity	1200 Gallons
Air Compressor	Gardner-Denver
Air Compressor Model	WBO
Air Brake Manufacturer	Westinghouse
Air Brake Schedule	6BL
Trucks	C-C
Truck Type	Flexicoil
Truck Wheelbase	13' 7"
Wheel Size	40"
Traction Motors	D37 (6), GM
Primary Generator	D12d, GM
Auxiliary Generator	Delco
Steam Generator (Optional)	Vapor-Clarkson (Model OK4625)
Alternator	D14
MU (Multiple-Unit)	Yes
Dynamic Brakes	Yes
Gear Ratio	62:15
Tractive Effort (Starting)	90,800 Lbs at 25%
Tractive Effort (Continuous)	75,000 Lbs at 9.3 mph
Top Speed	65 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.

Colorado & 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.