Classic Streamliners - TRAIN​CYCLOPEDIA

EMD SD7 Diesel-Electric Locomotive
The SD7 is a 6-axle road switcher diesel-electric locomotive built by General Motors Electro-Motive Division between May 1951 and November 1953. It had an EMD 567B 16-cylinder engine producing 1,500 horsepower (1.12 MW) for its six traction motors. 188 were built for United States railroads. Starting in August 1953 a total of 26 SD7s were produced which used either the 567BC engine or the 567C engine. These units are noted on the roster below.

This was the first model in EMD's SD (Special Duty) series of locomotives, a lengthened B-B GP7 with a C-C truck arrangement. The two extra axles and traction motors are useful in heavy, low speed freight service. SD series locomotives are still being produced today, with the SD70 being the most popular example in current production, and with many SD40-2s and rebuilds to SD40-2 specifications, or SD60s still in operation.

Yesterday's Special Duty eventually became today's Standard Duty, and yesterday's General Purpose has become today's Special Purpose ("time" freight and other time-sensitive lading). True GPs were discontinued after the completion of the last GP60 in 1994. Recently intermodal and other fast freights may be hauled by 6 axles locomotives with 4 powered axles, such as the SD70ACe-P4.

Many earlier model GPs, most particularly GP40s, GP39s and GP38s, also their SD equivalents, SD40s, SD39s, and 38s have been rebuilt to Dash 2 standards for another 30 to 40 years of service.

Original Buyers
Electro-Motive Division
Quantity: 2
Numbers: 990, 991
Notes: 990 to Southern Pacific 5308. 991 to Baltimore and Ohio 760.

Baltimore and Ohio Railroad
Quantity: 4
Numbers: 761–764
Notes: These units were built with the 567BC engine.

Bessemer and Lake Erie Railroad
Quantity: 8
Numbers: 451–455, 801–803

Chicago and North Western Railway
Quantity: 5
Numbers: 1660–1664

Chicago, Burlington and Quincy Railroad
Quantity: 37
Numbers: 300–324, 400–411
Notes: 322-324 were built with the 567BC engine.

Chicago, Milwaukee, St. Paul and Pacific Railroad
Quantity: 24
Numbers: 2200–2223
Notes: Renumbered 500–523, 2215-2223 were built with the 567BC engine.

Colorado and Southern Railway
Quantity: 10
Numbers: 810–819

Central of Georgia Railway
Quantity: 1
Numbers: 201

Denver and Rio Grande Western Railroad
Quantity: 5
Numbers: 5300–5304

Fort Worth and Denver Railway
Quantity: 11
Numbers: 850–860
Notes: 858-860 were built with the 567BC engine.

Great Northern Railway
Quantity: 23
Numbers: 550–572

Kennecott Copper Corporation
Quantity: 1
Numbers: Quantity: 903

Minneapolis and St. Louis Railway
Quantity: 2
Numbers: 852, 952
Notes: Renumbered 300–301.

Nevada Northern Railway
Quantity: 1
Numbers: 401

Pennsylvania Railroad
Quantity: 2
Numbers: 8588–8589
Notes: These units were built with the 567BC engine.

Southern Pacific Company
Quantity: 42
Numbers: 5279–5293, 5309–5335
Notes: 5321-5323, 5334-5335 were built with the 567C engine.

Union Pacific Railroad
Quantity: 10
Notes: Numbers: 775–784

Total Units Prodiuced:188

Preservation
The first SD7 (later converted into an SD7R) built by EMD, former demonstrator No. 990, Southern Pacific 1518, is preserved in operational condition at the Illinois Railway Museum.
Central of Georgia 201 is preserved at the Virginia Museum of Transportation.
The Dakota Southern Railway rosters two SD7's, No. 512, and No. 522 (Ex-WSOR No. 522, Exx-MILW No. 522, Exxx-MILW No. 2222).

EMD SD7 Overview
Type and origin
Power type: Diesel-electric
Builder: General Motors Electro-Motive Division (EMD)
Model: SD7
Build date: May 1951 – November 1953
Total produced: 188
Specifications
Configuration:
​ • AAR C-C
Gauge: 4 ft 8 1⁄2 in (1,435 mm) standard gauge
Trucks: EMD Flexicoil C
Wheel diameter: 40 in (1,016 mm)
Minimum curve: 23° (250 ft (76.20 m) radius)
Wheelbase: 48 ft 7 in (14.81 m)
Length: 61 ft 2 3⁄4 in (18.66 m)
Width: 10 ft 8 in (3.25 m)
Height: 15 ft 4 1⁄2 in (4.69 m)
Locomotive weight: 309,000 lb (140,000 kg)
Fuel capacity: 1,200 US gal (4,500 L; 1,000 imp gal)
Prime mover: EMD 567B
RPM range: 800
Engine type: V16 diesel engine
Aspiration: Roots-type supercharger
Displacement: 9,072 cu in (148.66 L)
Generator: D-12-C
Traction motors: (6) D-27-B
Cylinders: 16
Performance figures
Power output: 1,500 hp (1.12 MW)
Tractive effort: 77,250 lbf (343,600 N)
Career
Locale: United States
Disposition: some still in service

See also:

GM EMD Locomotives

GM Electro-Motive Division

Diesel-Electric Locomotives

Locomotives

Fort Worth and Denver EMD SD7 Diesel-Electric Road Switcher No. 855 at Hodges, Texas, February 25, 1971. Photo by Everett L. DeGolyer, Jr., SMU Digital Library.

Two of SP's then forty year old SD7's still at work switching the East end of the Roseville yard, February 2009.  Photo by Drew Jacksich.

By Drew Jacksich from San Jose, CA, The Republic of California (SP 1504 East end Rville Feb 1993xRP) [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

Two of SP's then forty year old SD7's still at work switching the East end of the Roseville yard, February 2009. Photo by Drew Jacksich.

Fort Worth and Denver EMD SD7 Diesel-Electric Road Switcher No. 855 at Hodges, Texas, February 25, 1971.  Photo by  Everett L. DeGolyer, Jr., SMU Digital Library.

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