||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (September 2012)|
|ITC 1605, at the Illinois Railway Museum|
|Builder||General Motors Electro-Motive Division (EMD)
General Motors Diesel (GMD/GMDD)
|Build date||October 1949 – May 1954|
|Total produced||2,729 (plus 5 B units)|
|AAR wheel arr.||B-B|
|Wheel diameter||40 in (1.016 m)|
|Length||56 ft 2 in (17.12 m)|
|Fuel capacity||1,600 US gal (6,100 l; 1,300 imp gal)|
|Lubricant capacity||200 US gal (760 l; 170 imp gal)|
|Coolant capacity||230 US gal (870 l; 190 imp gal)|
|Sandbox capacity||18 cu ft (510 dm3)|
|Prime mover||EMD 567B|
|Engine RPM range||275–800|
|Traction motors||EMD D27|
|Power output||1,500 hp (1,119 kW)|
|Tractive effort||Starting 65,000 lbf (290 kN) at 25% power|
|Locomotive brake||Independent air; optional: dynamic brakes|
|Train brakes||Air, schedule 6-BL or 6-BLC|
The EMD GP7 is a four-axle (B-B) road switcher diesel-electric locomotive built by General Motors Electro-Motive Division and General Motors Diesel between October, 1949 and May 1954. Power was provided by an EMD 567B 16-cylinder engine which generated 1,500 horsepower (1,119 kW). The GP7 was offered both with and without control cabs, and those built without control cabs were called a GP7B. The GP7B locomotives were built between March and April 1953. They were the first EMD road locomotives to use a hood unit design instead of a car-body design. This proved to be more efficient than the cab unit design as the hood unit cost less, had easier and cheaper maintenance, and had slightly better visibility.
Of the 2,734 GP7s built, 2,615 were for American railroads, 5 GP7B units were built for the Atchison, Topeka and Santa Fe Railway 112 were built for Canadian railroads, and 2 were built for Mexican railroads.
ALCO, Fairbanks-Morse, and Baldwin had all introduced road switchers before EMD, whose first attempt at the road-switcher, the BL2 was unsuccessful in the market, selling only 58 units in the 14 months it was in production. Its replacement, the GP7, swapped the truss-framed stressed car body for an un-stressed body on a frame made from flat, formed and rolled structural steel members and steel forgings welded into a single structure (a "weldment"), a basic design which is still being employed today. Unfortunately, in heavy service, the GP7’s frame would bow and sag over time. This defect was corrected in later models. The GP7 proved very popular, and EMD was barely able to meet demand, even after opening a second assembly plant at Cleveland, Ohio. Later, locomotives in EMD's GP-series came to be nicknamed ‘Geeps’. Many GP7s can still be found in service today, although most Class 1 roads stopped using these locomotives by the early 1980s.
The GP7, GP9 and GP18 locomotives share a similar car-body that evolved over time. Most GP7s had three sets of ventilation grills under the cab (where the GP9 only had one), and two pair of grills at the end of the long hood (where only the pair nearest the end was retained on the GP9). However, some late GP7s were built with car-bodies that were identical to early GP9s. Early GP7s had a solid skirt above the fuel tank, while late GP7s and early GP9s had access holes in the skirt (see photo of Illinois Terminal 1605, top left). Many railroads later removed most of the skirt to improve access and inspection.
Locomotives could be built with the engineer’s control stand installed for either the long hood, or the short hood designated as the front. Two control stands for either direction running was also an option, but one end would still be designated as the front for maintenance purposes. The GP7 was also available with or without dynamic brakes, and a steam generator installed in the short hood was also an option. In the latter case the 1,600 US gallons (6,100 l; 1,300 imp gal) fuel tank was divided, with half for diesel fuel, and half for boiler water. One option available for locomotives without dynamic brakes, was to remove the two 22.5 in × 102 in (571.5 mm × 2,590.8 mm) air reservoir tanks from under the frame, and replace them with four 12 in × 150.25 in (304.80 mm × 3,816.35 mm) tanks that were installed on the roof of the locomotive, above the prime mover. These “torpedo tubes” as they were nicknamed, enabled the fuel and water tanks to be increased to 1,100 US gallons (4,200 l; 920 imp gal) each, although some railroads opted for roof-mounted air tanks and 2,200 US gallons (8,300 l; 1,800 imp gal) fuel tanks on their freight ‘Geeps’.
Original buyers 
Locomotives built by Electro-Motive Division, USA 
Locomotives built by General Motors Diesel, Canada 
|Algoma Central and Hudson Bay||
|Canadian National Railways||
||4824 was a rebuild|
|Canadian Pacific Railway||
|Chesapeake and Ohio Railway||
|Quebec North Shore and Labrador Railway||
|Toronto, Hamilton and Buffalo Railway||
Modifications and conversions 
Many railroads rebuilt their GP7s with short hoods, some railroads went further in their rebuilding than others. Missouri Pacific Railroad upgraded their GP7s with 567BC engines and replaced the standard EMD 2-stack exhaust with a 4-stack “liberated” exhaust, raising their power output to 1,600 horsepower (1.19 MW).
Illinois Central Railroad rebuilt most of its GP7s with 567BC engine blocks, liberated exhausts, paper air-intake filters, 26-L brakes (their original 6-BL brakes made them operationally incompatible with locomotives fitted with 24-RL or 26-L brakes). All but the first locomotive rebuilt had their front (short) hood reduced in height for improved crew visibility. The IC designated these rebuilt locomotives GP8. The IC acquired many second-hand units through Precision National Corporation (PNC), and then started offering GP8 rebuilding services to other railroads.
One of the largest preserved rosters can be found in Portola, California, at the Western Pacific Railroad Museum. The WPRM is home to Western Pacific (WP) units 705, 707 and 708 and Sacramento Northern unit 712. WP 707 is fully restored and is maintained in mainline ready condition.
The Tennessee Valley Railroad Museum in Chattanooga, Tennessee, United States, also has a few operating GP7s. Visitors can charter one of these locomotives for an hour and operate it themselves (under the watchful eye of a TVRM engineer) along two miles (3 km) of TVRM's line. TVRM uses its GP7s not only for charters, but also for pulling excursion trains and for servicing its one industrial customer.
The Minnesota Transportation Museum operates a GP7 on its Osceola and St Croix Valley Railway. Painted as Soo Line 559, it was built as Rock Island 1223, rebuilt as their 4505, sold to the Chicago & North Western as their 4159, spun off to the Fox River Valley then acquired with the railroad by the Wisconsin Central. The locomotive was purchased by the museum from the Wisconsin Central.
The first production GP7, Chicago and North Western Railway 1518, along with Illinois Terminal GP7 1605 and Chicago & North Western 4160 - former Rock Island 1266, then 4506 - are preserved at the Illinois Railway Museum in Union, Illinois.
The Conway Scenic Railroad in North Conway, New Hampshire operates the former Maine Central RR GP-7 #573 on its valley train. #573 was the last MEC unit to retain an operating steam generator, and thus was used by railroad president E Spencer Miller on his inspection train. #573 is reputed to be the most painted unit on the Maine Central, and was known as "Mr. Miller's engine." To this day, the name of a MEC engineer, Jim Campbell, is still displayed on the inside of the short hood door in the cab, presumably placed there by Mr. Campbell during one of his trips in the unit.
The Lebanon Mason Monroe Railroad in Lebanon, Ohio operates one of the oldest GP7 locomotives. It was delivered by EMD in 1950 as C&O #5705 and was purchased by the Indiana and Ohio in 1987 to become #55. It is estimated to have run over 2.5 million miles (4 million km) to date.
The Orrville (Ohio)Railroad Heritage Society is currently (2012) operating the MEC 571 GP-7 (now repainted in ORHS colors and numbered 471). The locomotive was rebuilt by Amtrack in 1994 (now has a low short hood, dynamic brakes,a 645 rebuilt prime mover, a larger cab, and updated controls). It is used on short trips in Orrville, Ohio and on Operation Lifesaver, Santa Claus, and excursion trips on the W&LE railroad. See the www.orrvillerailroad.com website.
See also 
- Schrenk & Frey (1988) p.291
- IC Railroad 1969 diesel diagrams, pp.46–47
- Pinkepank, Jerry A. (1973) pp. 53
- NP Railway diesel diagram, NP 557–558
- The History of EMD Diesel Engines
- Pinkepank, Jerry A. (1973) p. 51
- Schren & Frey (1988). p.162
- NP Railway diesel diagram, NP 550–551
- Schrenk & Frey (1988). p.159
- Pinkepank, Jerry A. (1973) p.56
- Marre & Pinkepank (1988). p.192
- Marre & Pinkepank (1988). p.183
|Wikimedia Commons has media related to: EMD GP7 locomotives|
- "The History of EMD Diesel Engines". Pacific Southwest Railway Museum. Retrieved December 14, 2005.
- "Illinois Central Railroad 1969 locomotive diagram book". icgphotos.com. Retrieved September 2, 2008.
- "Northern Pacific Railway diesel locomotive diagrams". Northern Pacific Railway Historical Association website. Retrieved September 2, 2008.
- Ephraim Jr, Max The beloved Geep, Trains Magazine June 1995.
- Kristopans, A. J. "EMD 567 road switchers serial number webpage". Retrieved September 1, 2008.
- Kristopans, A. J. "General Motors Diesel Division (Canada) serial number webpage". Retrieved September 1, 2008.
- http://community-2.webtv.net/ajkristopans/ANDRESGMLOCOMOTIVE/page2.html Export GP7 serial numbers
- Marre, Louis A.; Jerry A. Pinkepank (1989). The Contemporary Diesel Spotter’s Guide. Milwaukee, Wisconsin: Kalmbach Publishing Company. ISBN 0-89024-088-4.
- Pinkepank, Jerry A. (1973). The Second Diesel Spotter’s Guide. Milwaukee, WI: Kalmbach Publishing Company. ISBN 0-89024-026-4.
- Schrenk, Lorenz P.; Robert L. Frey (1988). Northern Pacific Diesel Era (1945–1970). San Marino, California: Golden West Books. ISBN 0-87095-102-5.