EMD GP7

Infobox Locomotive
name=EMD GP7
powertype=Diesel-electric


caption=ITC 1605, at the Illinois Railway Museum
builder=General Motors Electro-Motive Division (EMD)
General Motors Diesel (GMD/GMDD)
builddate=October 1949 – May 1954
totalproduction=2,729 (and 5 B units)
aarwheels=B-B
wheeldiameter=convert|40|in|m|3|abbr=on
length=convert|56|ft|2|in|m|2|abbr=onIC Railroad 1969 diesel diagrams, pp.46–47]
fuelc
convert|1600|usgal|abbr=onSchrenk & Frey (1988) p.291]
sandc
convert|18|cuft|dm3|abbr=on
coolantc
convert|230|usgal|abbr=on
lubec
convert|200|usgal|abbr=on
rpmrange=275–800
generator=EMD D12
tractionmotors=EMD D27
primemover=EMD 567BPinkepank, Jerry A. (1973) pp. 53]
cylindercount=16
poweroutput=convert|1500|hp|MW|2|abbr=on|lk=on
locobrakes=Independent air; "optional:" dynamic brakes
trainbrakes=Air, schedule 6-BLor 6-BLCNP Railway diesel diagram, NP 557–558] The EMD GP7 is a four-axle 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 convert|1500|hp|MW|2|lk=on [The History of EMD Diesel Engines] . 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 of 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 vision.

Of the 2,729 GP7s built, 2,615 were for American railroads, 112 were for Canadian railroads, and 2 were for Mexican railroads. All 5 GP7Bs were built for the Atchison, Topeka and Santa Fe Railway.Pinkepank, Jerry A. (1973) p.56]

History

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. [Pinkepank, Jerry A. (1973) p. 51] Its replacement, the GP7, swapped the truss-framed stressed car body for the un-stressed body on a flatcar-like frame that EMD’s competitors had used on their road-switchers from the start. Unfortunately, in heavy service, the GP7’s frame would bow and sag over time. 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 Rail carriers stopped using these locomotives by the early 1980s.

Identification

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 convert|1600|usgal 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 convert|22.5|x|102|in|m|2|abbr=onNP Railway diesel diagram, NP 550–551] air reservoir tanks from under the frame, and replace them with four convert|12|x|150.25|in|m|2|abbr=on 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 convert|1100|usgal each, although some railroads opted for roof-mounted air tanks and convert|2200|usgalSchrenk & Frey (1988). p.159] fuel tanks on their freight ‘Geeps’.

Original buyers

Locomotives built by Electro-Motive Division, USA

Locomotives built by General Motors Diesel, Canada

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 convert|1600|hp|MW|2.Marre & Pinkepank (1988). p.192]

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)Marre & Pinkepank (1988). p.183] . 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.

Preservation

The GP7 can still be seen on Short-line railroads and in museums. This long lasting road switcher is good for any job, making it the ideal industrial locomotive.

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 United Railways Historical Society owns two former NJT, ex CR, nee Central Railroad of New Jersey GP7Ps, #1523 and 1524.

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 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, is preserved at the Illinois Railway Museum in Union, Illinois.

The Conway Scenic Railroad in North Conway, New Hamppshire 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.

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