EMD SD7

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EMD SD7
SP 1518 20050716 Illinois Railway Museum.JPG
Type and origin
Power type Diesel-electric
Builder General Motors Electro-Motive Division (EMD)
Model SD7
Build date February 1952 – November 1953
Total produced 188
Specifications
AAR wheel arr. C-C
Gauge 4 ft 8 12 in (1,435 mm)
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 34 in (18.66 m)
Width 10 ft 8 in (3.25 m)
Height 15 ft 4 12 in (4.69 m)
Locomotive weight 309,000 lb (140,000 kg)
Fuel capacity 1,200 US gal (4,500 L)
Prime mover EMD 567B
Engine RPM range 800
Engine type Two-stroke diesel
Aspiration Roots-type supercharger
Displacement 9,072 cu in (148.66 L)
Generator D-12-C
Traction motors (6) D-27-B
Cylinders V16
Performance figures
Power output 1,500 hp (1.12 MW)
Tractive effort 77250
Career
Locale United States
Disposition some still in service

An SD7 is a 6-axle road switcher diesel-electric locomotive built by General Motors Electro-Motive Division between February 1952 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.[1]

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,[2] 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. However, many earlier model GPs, most particularly GP40s, GP39s and GP38s, also their SD equivalents, SD40s, SD39s and SD38s have been rebuilt to Dash 2 standards for another 30 to 40 years of service.

Original buyers[edit]


Owner Quantity Numbers Notes
Electro-Motive Division
2
990
to Southern Pacific 5308
991
to Baltimore and Ohio 760
Baltimore and Ohio Railroad
4
761–764
Bessemer and Lake Erie Railroad
8
451–455, 801–803
Chicago and North Western Railway
5
1660–1664
Chicago, Burlington and Quincy Railroad
37
300–324, 400–411
Chicago, Milwaukee, St. Paul and Pacific Railroad
24
2200–2223
Renumbered 500–523
Colorado and Southern Railway
10
810–819
Central of Georgia Railway
1
201
Denver and Rio Grande Western Railroad
5
5300–5304
Fort Worth and Denver Railway
11
850–860
Great Northern Railway
23
560–572
Kennecott Copper Corporation
1
903
Minneapolis and St. Louis Railway
2
852, 952
Renumbered 300–301
Nevada Northern Railway
1
401
Pennsylvania Railroad
2
8588–8589
Southern Pacific Company
42
5279–5293, 5309–5335
Union Pacific Railroad
10
775–784
Total 188

Preservation[edit]

  • Central of Georgia 201 is preserved at the Virginia Museum of Transportation.

References[edit]

  1. ^ Pinkpank, Jerry A (1973). The Second Diesel Spotter’s Guide. Kalmbach Books. p. 71. LCCN 66-22894. 
  2. ^ Ross, David, ed. (2003). The Encyclopedia of Trains and Locomotives. pp. 281, 364, 368–369. ISBN 978-0-7607-9679-5.