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Background Information

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D&RGW #5634 in 1950; this early Phase I locomotive was delivered in July, 1949
Power type Diesel-electric
Builder General Motors Electro-Motive Division (EMD)
General Motors Diesel (GMD, Canada)
Model F7
Build date February 1949 – December 1953
Total produced 2,366 A units, 1,483 B units
AAR wheel arr. B-B
Gauge ft 8 12  in (1,435  mm)
Wheel diameter 40 in (1.016 m)
Length A unit: 50 ft 8 in (15.44 m)
B unit: 50 ft 0 in (15.24 m)
Width 10 ft 7 in (3.23 m)
Prime mover EMD 567
Cylinders V16
Power output 1,500  hp (1,100  kW)
Locale North America

The EMD F7 was a 1,500 horsepower B-B Diesel-electric locomotive produced between February, 1949 and December, 1953 by General Motors' Electro-Motive Division and General Motors Diesel. It succeeded the F3 model in GM-EMD's F-unit sequence, and was replaced in turn by the F9. Final assembly was at GM-EMD's La Grange, Illinois plant or GMD's London, Ontario facility. Although originally promoted as a freight-hauling unit by EMD, the F7 was also used in passenger service hauling such trains as the Santa Fe's El Capitan.

A total of 2,366 cab-equipped lead A-units and 1,483 cabless booster or B-units were built. The F7 was the fourth model in GM-EMD's highly successful F-unit series of cab unit locomotives, and was, prior to the introduction of the EMD SD40-2 freight unit, the best selling Diesel-electric locomotive of all time.

Many F7s remained in service for decades, as railroads found them economical to operate and maintain. However the locomotive was not very popular with the 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 his 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 "GP" type "road switchers", Fs were primarily used in "through freight" and "unit train" service where there was very little or no switching to be done on line of road.

The F7 can be considered the zenith of the cab unit freight Diesel, as it was ubiquitous on North American railroads until the 1970s (longer in Canada). The F7 design has become entrenched in the popular imagination due to it having been the motive power of some of the most famous trains in North American railroad history.

The F7 replaced the F3, differing primarily in internal equipment (mostly electrical) and some external features. The F7 was eventually succeeded by the more powerful but mechanically similar F9.


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 of most F3s, and no F3s had the later F7 changes described below under Phases.

The EMD F9 is distinguishable from the late F7 by having five, rather than four, carbody centre louver groups covering the carbody filters. The additional one is placed ahead of the first porthole, where F7s have no openings. The F9s greater power output, of course, cannot be seen from the outside.


The identification of locomotive "phases" is a creation of railfans. EMD used no such identification, and instead kept track of the marketing name (F7) and individual locomotives' build numbers. During the production cycle of a model, EMD would often make detail changes that were not readily apparent to the casual observer. To keep better track of the variations of locomotives identified the same by the manufacturer, railfans began referring to phases (critical changes to a locomotive line).

Despite not being official designations, the phase description is useful. However, many of the changes described are cosmetic, easily changed features of a locomotive: e.g., roof fans, body panels, grilles and the like could be and sometimes were updated or swapped. Most of the phase differences on the F7 were concerned only with A units; B units varied far less. The following are normally identified as F7 phases:

Phase I (early)

Built from February 1949. Upper grille with horizontal openings. Four horizontal louvred openings on centre body panel. 36 inch dynamic brake fan, if dynamic brakes fitted. Flush windshield gasket changed to raised in July 1949. Square cab door corners with kick plates on the steps beneath. Wing window short with square corners. Single drip strip over cab windows and door. Square end door window. Round sand filler cover. Rear overhang.

Phase I (late)

Built from March 1950. Upper grille started out horizontal, as in early Phase I; from March 1951, some locomotives were built with vertical-slotted "Farr-Air" grilles, and by October 1951, all had them. Cab doors became round-cornered, and the kick plates were deleted. The wing windows became larger, with round corners. Two drip strips; one over cab windows, second over door. The end door window became round after November 1950.

Phase II

Built from February 1952. All upper grilles vertical "Farr-Air" type. Centre car body louvres became vertical-slotted. Sand filler now with a horizontal, rectangular pull handle. From June 1952, 48 inch dynamic brake fans began to be introduced; from October 1952, all dynamic-brake equipped locomotives had them. At that latter date, locomotives no longer had a rear overhang.

Original buyers

Owner Cab-equipped 'A' units Cabless booster 'B' units


The Western Pacific Railroad Museum at Portola, CA rosters two former Western Pacific Railroad F7As: WP 917-D and 921-D. These engines are part of the museum's popular "Run a locomotive" program.

The California State Railroad Museum in Sacramento, CA has the former Western Pacific F7A 913. This engine is operational.

The Fillmore and Western Railway in Fillmore, CA has two F7As that are operational.

The Monticello Railway Museum in Monticello, IL allows guests to operate their Wabash Railroad F7A #1189 for a donation through the "Throttle Time" program.

The North Carolina Transportation Museum, Spencer, NC, has former Southern Railway FP-7 6133 in operating condition, with Southern colors.

The Baltimore & Ohio Railroad Museum, Baltimore, MD, has former Western Maryland Railway F7A 236 in operating condition.

The Boston & Maine Railroad had 4 F7A's with accompanying B units, numbered 4265-4268 (A & B). #4267A was demolished in a derailment. #4266 survives at this writing, at the Conway Scenic RR in North Conway NH, where it is rostered as a spare unit and operated frequently. It is owned by the 470 RR Club of Portland ME and operated under a lease agreement with CSRR. #4268 is also owned by the 470 Club, and is on static display (exterior only) at CSRR. The prime mover has been removed.

  1. 4268 is on static display at the Gorham NH Historical Society at the former Grand Trunk RR depot in Gorham. It is also inoperable.
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