EMD SD7

An 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.[1] 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.

EMD SD7
SP 1518 at the Illinois Railway Museum
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) Loco 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

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. Recently intermodal and other fast freights may be hauled by 6 axles locomotives with 4 powered axles, such as the SD70ACe-P4.

Many SD7s both high and short-hood can still be found in service today on shortline railroads and industrial operators, although most Class 1 roads stopped using these locomotives by the 1970s and 1980s. Some remain in rebuilt form on some major Class I railroads, as switcher locomotives..

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

Owner	Quantity	Numbers	Notes
Electro-Motive Division	2	990	to Southern Pacific 5308 then 2715 to 1415 ne 1518
		991	to Baltimore and Ohio 760
Baltimore and Ohio Railroad	4	761–764	These units were built with the 567BC engine.
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	322-324 were built with the 567BC engine. To Burlington Northern 6023-6059
Chicago, Burlington and Quincy Railroad (Colorado and Southern Railway)	10	810–819	To Burlington Northern 6070-6079
Chicago, Burlington and Quincy Railroad (Fort Worth and Denver Railway)	11	850–860	858-860 were built with the 567BC engine. To Burlington Northern 6080-6090
Chicago, Milwaukee, St. Paul and Pacific Railroad	24	2200–2223	Renumbered 500–523, 2215-2223 were built with the 567BC engine.
Central of Georgia Railway	1	201
Denver and Rio Grande Western Railroad	5	5300–5304
Great Northern Railway	23	550–572	To Burlington Northern 6000-6022
Kennecott Copper Corporation	1	903
Minneapolis and St. Louis Railway	2	852, 952	Renumbered 300–301. To Chicago and North Western Railway.
Nevada Northern Railway	1	401
Pennsylvania Railroad	2	8588–8589	These units were built with the 567BC engine
Southern Pacific Company	42	5279–5293, 5309–5335	5321-5323, 5334-5335 were built with the 567C engine
Union Pacific Railroad	10	775–784
Total	188

Preservation

• The first SD7 (later converted into an SD7R) built by EMD, Southern Pacific 1518 (demonstrator #990), is preserved in operational condition at the Illinois Railway Museum.
• Southern 197 is preserved at the Virginia Museum of Transportation. It was originally built as Central of Georgia 201.
• The Dakota Southern Railway rosters two SD7's, #512, and #522 (512 and 522 are ex-MILW #2212 and #2222).
• Burlington Northern #6008, one of the first 20 SD7s to be built in 1952, is preserved and in restoration to its original appearance as Great Northern #558 at the Minnesota Transportation Museum.
• Former Pennsylvania Railroad 8589 is in operation at Red Trail Energy in Richardton ND as 1751 with a chopped nose.
• Nevada Northern Railway 401 is in service at one of LADWP’s power plants in Delta, Utah. When retired, it will be donated to the Nevada Northern Railway Museum, as part of an agreement.

References

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.

• Dorin, Patrick C. (1972). Chicago and North Western Power. Burbank, California: Superior Publishing. p. 114. ISBN 0-87564-715-4.
• Pinkpank, Jerry A (1973). The Second Diesel Spotter’s Guide. Kalmbach Books. pp. 17, 26, 71–72. ISBN 0-89024-026-4. LCCN 66-22894.
• Sarberenyi, Robert. EMD SD7 Original Owners. Retrieved on August 27, 2006
• Diesel Era Volume 6 Number 6 November/December 1995, "EMD's SD7" by Paul K. Withers pp 5-20; 47-50.
• EMD Product Reference Data Card dated January 1, 1959 has the 567BC and 567C engine data used in the as-built roster.

External links

• Locomotive Truck EMD FlexiCoil C