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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. Five GP7B's were built between March and April 1953. The GP7 was the first EMD road locomotive to use a hood unit design instead of a car-body design. This proved to be more efficient than the car body design as the hood unit cost less to build, was cheaper and easier to maintain, and had much better front and rear visibility for switching.
Of the 2,734 GP7's built, 2,620 were for American railroads (including 5 GP7B units built for the Atchison, Topeka and Santa Fe Railway), 112 were built for Canadian railroads, and 2 were built for Mexican railroads.
This was the first model in EMD's GP (General Purpose) series of locomotives. Concurrently, EMD offered a six-axle (C-C) SD (Special Duty) locomotive, the SD7. The GP7 was replaced by the GP9 model in GM-EMD's GP sequence.
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 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 1980s some remain in rebuilt form on some major Class I railroads, as switcher locomotives.. The "GP" designation stood for "general purpose", while the "7" had no meaning other than matching the EMD F7 cab unit then in production.
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'.
|Electro-Motive Division (demonstrator)||1350 hp GP7m; to Atchison, Topeka and Santa Fe 99, renumbered 2899 This unit was built with a 567BC engine.|
|to Chicago & North Western 1518-1520|
|Aberdeen and Rockfish Railroad|
|Atchison, Topeka and Santa Fe||2855-2858 were built with 567C engines|
|GP7B; 2788A-2789A, 2791A-2792A were built with 567C engines|
|Atlanta and St. Andrews Bay|
|Atlanta and West Point Rail Road|
|Atlantic and East Carolina Railway|
|Atlantic Coast Line Railroad|
|Baltimore and Ohio Railroad||728-729; 740-746 were built with 567BC engines|
|Bangor and Aroostook Railroad|
|Belt Railway of Chicago|
|Boston and Maine Railroad|
|Butte, Anaconda and Pacific Railway|
|Central of Georgia Railway|
|Central Railroad of New Jersey|
|Atlantic Coast Line Railroad (C&WC)|
|Chesapeake and Ohio Railway||5720-5738 built by GMD|
|Chicago and Eastern Illinois Railroad|
|Chicago and North Western Railway|
|Chicago and North Western (Chicago, St. Paul, Minneapolis and Omaha Railway--"Omaha Road")|
|Chicago, Burlington and Quincy Railroad||253-267 were built with 567BC engines|
|Chicago Great Western Railway|
|Chicago, Rock Island and Pacific Railroad||1294-1299 were built with 567BC engines|
|Colorado and Wyoming Railway|
|Colorado Fuel and Iron|
|Atlantic Coast Line Railroad (CN&L)|
|Delaware, Lackawanna and Western Railroad||To Erie Lackawanna|
|Denver and Rio Grande Western Railroad|
|Detroit and Toledo Shore Line Railroad|
|Detroit, Toledo and Ironton Railroad||964-973 were built with 567BC engines|
|Erie Railroad||To Erie Lackawanna|
|Florida East Coast Railway|
|Georgia and Florida Railroad|
|Georgia Railroad||1035-1036 were built with 567BC engines|
|Great Northern Railway|
|Illinois Central Railroad||8800-8801, 8900-8911 had steam generators|
|Illinois Terminal Railroad|
|Kansas City Southern Railway|
|Kansas City Southern (Louisiana and Arkansas Railway)|
|Kansas, Oklahoma and Gulf Railway|
|Louisville and Nashville Railroad|
|Maine Central Railroad||566-569 were built with 567BC engines|
|Meridian and Bigbee Railroad|
|Midland Valley Railroad|
|Minneapolis, St. Paul and Sault Ste. Marie Railroad ("Soo Line")|
|Missouri Pacific Railroad||29 units owned by International-Great Northern Railroad, 28 by St. Louis, Brownsville and Mexico Railway; 4290-4291, 4316-4320, 4325 were built with 567BC engines; 4292-4315, 4321-4324 were built with 567C engines.|
|Missouri-Kansas-Texas Railroad||1700s had steam generators. Renumbered 91-123|
|Nashville, Chattanooga and St. Louis Railway||700-705 built with EMD AAR TypeA trucks|
|Ferrocarriles Nacionales de México|
|New York Central Railroad||35 units owned by Pittsburgh and Lake Erie Railroad (5676-5685, 5713-5737); 14 by Peoria and Eastern Railway (5612-5625)|
|New York, Chicago and St. Louis Railroad ("Nickel Plate Road")|
|Northern Pacific Railway||to Burlington Northern Railroad 1624-1643; 560-569 were built with 567BC engines|
|Phelps Dodge Corporation|
|Portland Terminal Company [Maine]|
|Reading Company||625-636 were built with 567BC engines|
|Richmond, Fredericksburg and Potomac Railroad|
|Seaboard Air Line Railroad|
|Southern Railway (Cincinnati, New Orleans and Texas Pacific Railway)|
|Southern Railway (Alabama Great Southern Railroad)|
|Southern Railway (Georgia Southern and Florida Railway)|
|St. Louis Southwestern Railway||Renumbered to 304|
|St. Louis-San Francisco Railway|
|Tennessee, Alabama and Georgia Railway|
|Texas and Pacific Railway|
|Texas Mexican Railway|
|Toledo, Peoria and Western Railway|
|Union Pacific Railroad||720-729 were built with 567BC engines|
|United States Army||Built with EMD AAR TypeA trucks; 12 later served on Alaska RR and 11 were retrucked with AAR Type B road trucks|
|Wabash Railroad||453 built by GMD|
|Western Maryland Railway|
|Western Pacific Railroad|
|Western Railway of Alabama|
|Algoma Central and Hudson Bay|
|Canadian National Railways||4824 rebuilt October 1958 with parts from wrecked F3A.|
|Canadian Pacific Railway|
|Chesapeake and Ohio Railway|
|Quebec North Shore and Labrador Railway|
|Toronto, Hamilton and Buffalo Railway|
There are five GP7s on A J Kristopan's EMD Serial number page that reused previous serial numbers: B&O 6405, CRI&P 1308 (2nd), L&N 501 (2nd) and 502 (2nd), and SLSF 615 (2nd). These rebuilt units were rebuilt as new on new frames. Another rebuild by GMD is that CN 4824 was rebuilt as a GP7 with parts from an F3A in October 1958.
Over 100 GP7s and four of the GP7Bs were built with 567BC or 567C engines starting in March 1953 through May 1954. These are noted on the roster above.
Many railroads rebuilt their GP7s with low 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 engines, liberated exhausts, paper air-intake filters, 26-L brakes (their original 6-BL brakes made them operationally incompatible with locomotives fitted with 24-RL 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.
In 1960 the Alaska Railroad purchased a dozen GP7Ls from the US Army and rebuilt eleven of them in 1965 with low short hoods for better visual clearance. One of the ten remaining Alaska GP7s was rebuilt by Morse-Knudsen in 1976. The other nine units were rebuilt at Paducah Shops in 1976-1977.
Numerous GP7s have been preserved on tourist lines and in museums. Holders include:
EMD Product Reference Data Card dated January 1, 1959 has the 567BC and 567C engine data used in the as-built roster.