EMD SD7

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 AAR wheel arr. 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

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
AAR wheel arr.	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

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. 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 SD38s have been rebuilt to Dash 2 standards for another 30 to 40 years of service.

...
Wikipedia