The EMD F7 is a model of

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the power source is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...

produced between February 1949 and December 1953 by the Electro-Motive Division of General Motors (EMD) and

General Motors Diesel General Motors Diesel was a railway diesel locomotive manufacturer located in London, Ontario, Canada. It was established in 1949 as the Canadian subsidiary of the Electro-Motive Diesel division of General Motors (EMD). In 1969 it was re-organiz ...

(GMD). Although originally promoted by EMD as a

freight In transportation, cargo refers to goods transported by land, water or air, while freight refers to its conveyance. In economics, freight refers to goods transported at a freight rate for commercial gain. The term cargo is also used in ...

-hauling unit, the F7 was also capable of passenger service, and used in hauling trains such as the

Santa Fe Railway The Atchison, Topeka and Santa Fe Railway , often referred to as the Santa Fe or AT&SF, was one of the largest Railroad classes, Class 1 railroads in the United States between 1859 and 1996. The Santa Fe was a pioneer in intermodal freight tra ...

's high-speed flagship trains, the ''

Super Chief The ''Super Chief'' was one of the List of named passenger trains, named train, passenger trains and the flagship of the Atchison, Topeka and Santa Fe Railway. The then-modern streamliner was touted in its heyday as "The Train of the Stars" b ...

, &

El Capitan El Capitan (; ) is a vertical Rock formations in the United States, rock formation in Yosemite National Park, on the north side of Yosemite Valley, near its western end. The El Capitan Granite, granite monolith is about from base to summit alo ...

'', and the

Ontario Northland The Ontario Northland Transportation Commission (ONTC), or simply Ontario Northland, is a Crown agency of the Government of Ontario responsible for providing transportation services for passengers and goods in Northern Ontario. It reports to ...

's ''

Northlander The ''Northlander'' was a passenger train operated by the provincially-owned Ontario Northland Railway in southern and northeastern Ontario, Canada. In 2012, rail service was discontinued and replaced with express bus service. Rail service will ...

''.

History

The F7 was the fourth model in GM-EMD's successful line of F-unit locomotives, and by far the best-selling

cab unit In North American railroad terminology, a cab unit is a railroad locomotive with its own cab and controls. "Carbody unit" is a related term, which may be either a cabless booster unit controlled from a linked cab unit, or a cab unit that con ...

of all time. In fact, more F7s were built than all other F-units combined. The F7 succeeded the F3 model in GM-EMD's F-unit series, and was replaced in turn by the F9. Final assembly was at GM-EMD's

La Grange, Illinois La Grange ( ; often spelled LaGrange) is a village (United States)#Illinois, village in Cook County, Illinois, United States. It is a suburb of Chicago. The population was 16,321 at the 2020 census. History The area around La Grange was first s ...

, plant or GMD's

London, Ontario London is a city in southwestern Ontario, Canada, along the Quebec City–Windsor Corridor. The city had a population of 422,324 according to the 2021 Canadian census. London is at the confluence of the Thames River (Ontario), Thames River and N ...

, facility. There was no F4, -5 or -6 model; "7" was chosen to match the contemporary twin-engine E7, and was also applied to the new

GP7 GP-7 or GP7 may refer to: Vehicular * EMD ''GP7'', a class of locomotives * Ducati ''GP7'', a model of the racing motorcycle Ducati ''Desmosedici'' * Honda ''GP7'', a model of the subcompact Honda ''Fit Shuttle'' Other uses * (48616) 1995 GP7, a ...

road-switcher. The F7 differed from the F3 primarily in internal equipment—mostly electrical—and some external features. Its continuous

tractive effort In railway engineering, the term tractive effort describes the pulling or pushing capability of a locomotive. The published tractive force value for any vehicle may be theoretical—that is, calculated from known or implied mechanical proper ...

rating was 20 percent higher, e.g. for an F7 with gearing, compared to for an F3 with the same gearing. Many F7s remained in service for decades, as railroads found them economical to operate and maintain. However, the locomotive was not very popular with yard crews who operated them in switching service because they were difficult to mount and dismount, and it was also nearly impossible for the engineer to see hand signals from a ground crew without leaning way outside the window. As most of these engines were bought and operated before two-way radio became standard on most American railroads, this was a major point of contention. In later years, with the advent of the "road switchers" such as the

EMD GP7 The EMD GP7 is a four-axle (AAR wheel arrangement#B-B, B-B) diesel-electric locomotive built by General Motors Electro-Motive Division and General Motors Diesel between October 1949 and May 1954.Pinkepank, Jerry A. (1973) pp. 53 The GP7 was ...

, F-units were primarily used in "through freight" and "

unit train A unit train, also called a block train or a trainload service, is a train in which all cars (wagons) carry the same commodity and are shipped from the same origin to the same destination, without being split up or stored en route. They are disti ...

" service where there was little or no switching to be done.

Engine and powertrain

The F7's

prime mover Prime mover may refer to: Philosophy *Unmoved mover, a concept in Aristotle's writings Engineering * Prime mover (engine or motor), a machine that converts various other forms of energy (chemical, electrical, fluid pressure/flow, etc.) into ener ...

is a 16-cylinder 567B series

diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...

developing at 800 rpm. The 567B is a mechanically aspirated

two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes of the piston, one up and one down, in one revolution of the crankshaft in contrast to a four-stroke engine which re ...

design in a 45-degree

V engine A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder ...

configuration, with displacement per cylinder, for a total of . A direct current generator that is mechanically coupled to the

flywheel A flywheel is a mechanical device that uses the conservation of angular momentum to store rotational energy, a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, a ...

end of the engine powers four

traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, or electric multiple unit trains. Traction (engineering), Traction motors are used in electrically powe ...

s, with two motors mounted on each

Blomberg B The Blomberg B is a 2-axle bogie that was introduced by EMD in 1939 with the FT locomotive series; the original "B" version plus later "M" and "X" versions were quite successful and became standard equipment on a multitude of locomotive models. ...

truck. EMD has built all of its major components since 1939.

Identification

There are no easily identifiable differences between late F3 production and early F7 production; the major differences were all internal electrical system changes. However, no F7 had the "chicken wire" grilles seen on most F3s, and no F3s had later F7 changes described below under ''Phases''. The F9 is distinguishable from the late F7 by having five, rather than four, carbody center louver groups covering the carbody filters. The additional one is placed ahead of the first porthole, where F7s have no openings. The F9's greater power output, of course, cannot be seen from the outside. There were also two main classes of F7s: passenger and freight. Most passenger units had upper and lower headlights, but there were exceptions. Many freight units had the upper

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

or Pyle brand warning light as well. And some passenger units only had a single upper headlight, i.e. the Pennsylvania. Many units eventually had the upper lights or the door light removed/plated over and the Mars/Pyle light removed. These early warning lights had a motor and linkages that often required maintenance in the shops.

Rebuilds

MARC 83 at Brunswick MD June 1994xRP - Flickr - drewj1946

Several F7s were rebuilt by

Morrison–Knudsen Morrison–Knudsen (MK) was an American civil engineering and construction company, with headquarters in Boise, Idaho. MK designed and constructed major infrastructure throughout the world and was one of the consortium of firms that built Hoover ...

as F9PHs and used in passenger operations. Others were rebuilt as the " FP10" and used by the

Massachusetts Bay Transportation Authority The Massachusetts Bay Transportation Authority (abbreviated MBTA and known colloquially as "the T") is the public agency responsible for operating most public transportation services in Greater Boston, Massachusetts. The MBTA transit network in ...

for their commuter rail service. In addition, the Santa Fe had 190 of their F7As rebuilt into

CF7 The Santa Fe CF7 is an EMD F-unit railroad locomotive that has had its in order to adapt the unit for switcher, switching duty. All of the conversions were performed by the Atchison, Topeka & Santa Fe Railway's Cleburne, Texas, workshops between ...

hood units in the 1970s. Only one original F7 unit from the railway exists to this day, preserved in running condition at the

California State Railroad Museum The California State Railroad Museum is a museum in the California State Parks system that interprets the role of railroads in the Western U.S. It is located in Old Sacramento State Historic Park at 111 I Street, Sacramento, California. Featu ...

in Sacramento. In the early 2000s, a single unpowered EMD F cab unit #7100 (ex-Baltimore & Ohio Railroad F7 #4553) operated on

MARC Marc or MARC may refer to: People * Marc (given name), people with the first name * Marc (surname), people with the family name Acronyms * MARC standards, a data format used for library cataloging, * MARC Train, a regional commuter rail system ...

, occasionally substituting for a cab car. In addition to serving as an all-purpose control unit, it also had a head-end power generator that supplied electricity to the train.

Original owners

A total of 2,393 cab-equipped lead

A unit An A-unit, in railroad terminology, is a diesel locomotive (or more rarely an electric locomotive) equipped with a driving cab and a control system to control other locomotives in a multiple unit, and therefore able to be the lead unit in a c ...

s and 1,463 cabless-booster or

B unit A B-unit, in railroad terminology, is a locomotive unit (generally a diesel locomotive) which does not have a control cab or crew compartment, and must therefore be operated in tandem with another coupled locomotive with a cab (an A-unit) ...

s were built. Roughly fifty railroads purchased A units, B units, or both. The single largest buyer was the

Southern Pacific Railroad The Southern Pacific (or Espee from the railroad initials) was an American Railroad classes#Class I, Class I Rail transport, railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was oper ...

, which purchased 294 A units and 236 B units. Other significant buyers included the

Atchison, Topeka and Santa Fe Railway The Atchison, Topeka and Santa Fe Railway , often referred to as the Santa Fe or AT&SF, was one of the largest Class 1 railroads in the United States between 1859 and 1996. The Santa Fe was a pioneer in intermodal freight transport; at vario ...

, the

New York Central Railroad The New York Central Railroad was a railroad primarily operating in the Great Lakes region, Great Lakes and Mid-Atlantic (United States), Mid-Atlantic regions of the United States. The railroad primarily connected New York metropolitan area, gr ...

, the

Baltimore and Ohio Railroad The Baltimore and Ohio Railroad was the oldest railroads in North America, oldest railroad in the United States and the first steam engine, steam-operated common carrier. Construction of the line began in 1828, and it operated as B&O from 1830 ...

, and the

Pennsylvania Railroad The Pennsylvania Railroad ( reporting mark PRR), legal name as the Pennsylvania Railroad Company, also known as the "Pennsy," was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. At its ...

. Locomotives intended for use in Canada were built by

, EMD's Canadian subsidiary. These included 76 for the

Canadian National Railway The Canadian National Railway Company () is a Canadian Class I freight railway headquartered in Montreal, Quebec, which serves Canada and the Midwestern and Southern United States. CN is Canada's largest railway, in terms of both revenue a ...

and 29 for the

Canadian Pacific Railway The Canadian Pacific Railway () , also known simply as CPR or Canadian Pacific and formerly as CP Rail (1968–1996), is a Canadian Class I railway incorporated in 1881. The railway is owned by Canadian Pacific Kansas City, Canadian Pacific Ka ...

. The

Wabash Railroad The Wabash Railroad was a Class I railroad that operated in the mid-central United States. It served a large area, including track in the states of Ohio, Indiana, Illinois, Iowa, Michigan, and Missouri and the province of Ontario. Its primary con ...

, although primarily an American railroad, purchased locomotives from both EMD and GMD. The

Ferrocarriles Nacionales de México ''Ferrocarriles Nacionales de México'' (better known as N de M and after 1987 as Ferronales or FNM) or ''National Railways of Mexico'' was Mexico's state owned railroad company from 1938 to 1998, and prior to 1938 (dating from the regime of P ...

's (NdeM) 39 locomotives were built in the United States.

Surviving units

Conway Scenic Railroad Engine New Hampshire

Several F7s are preserved at shortlines, tourist lines, and museums, including: *

Aberdeen, Carolina and Western Railway The Aberdeen, Carolina and Western Railway is a short-line railroad running from Aberdeen to Star, North Carolina. It was incorporated in 1987 and operates on a former Norfolk Southern Railway branch line. It also leases track from Norfolk Sout ...

Boone and Scenic Valley Railroad The Boone and Scenic Valley Railroad is a heritage railroad that operates freight and passenger excursions in Boone County, Iowa. History The heritage and excursion railroad was begun in 1983 by a group of volunteers who wanted to preserve a sc ...

Conway Scenic Railroad The Conway Scenic Railroad is a heritage railroad located in North Conway, New Hampshire, owned by Profile Mountain Holdings Corp. The railroad operates over two historic railway routes: a line from North Conway to Conway that was formerly par ...

* Don Rhodes Mining and Transport Museum *

Galveston Railroad Museum The Galveston Railroad Museum is a railroad museum housed in the former Santa Fe Railroad station, at 25th and Strand in Galveston, Texas. The Museum is owned and operated by the Center for Transportation and Commerce, a non-profit organizatio ...

Illinois Railway Museum The Illinois Railway Museum (IRM, reporting mark IRMX) is the largest railroad museum in the United States. It is located in the Chicago metropolitan area at 7000 Olson Road in Union, Illinois, northwest of downtown Chicago. Overview ...

Manitoba Children's Museum The Manitoba Children's Museum is a non-profit, charitable children's museum located at The Forks, Winnipeg, The Forks in Winnipeg, Manitoba, Canada. History The museum was founded in 1983. It opened its first exhibit in a warehouse on 21 June ...

* Museum of Alaska Transportation & Industry
Oregon Coast Scenic Railroad
*

Reading Blue Mountain and Northern Railroad The Reading Blue Mountain and Northern Railroad , sometimes shortened to Reading and Northern Railroad, is a regional railroad in eastern Pennsylvania. With a headquarters in Port Clinton, the RBMN provides freight service on over of track. Its ...

Notes

References

* * * *

External links

Roster
{{EMD cab and cowl B-B locomotives F07 F07 Diesel–electric locomotives of the United States Railway locomotives introduced in 1949 Locomotives with cabless variants Standard-gauge locomotives of the United States Passenger locomotives Standard-gauge locomotives of Canada Standard-gauge locomotives of Mexico Diesel–electric locomotives of Canada Diesel–electric locomotives of Mexico Streamlined diesel locomotives Atchison, Topeka and Santa Fe Railway locomotives Baltimore and Ohio locomotives Canadian National Railway locomotives Canadian Pacific Railway locomotives New York Central Railroad locomotives Pennsylvania Railroad locomotives Southern Pacific Railroad locomotives