The EMD F7 was a 1,500 horsepower (1,100 kW) Diesel-electric locomotive produced between February 1949 and December 1953 by the Electro-Motive Division of General Motors (EMD) and General Motors Diesel (GMD).
Although originally promoted by EMD as a freight-hauling unit, the F7 was also used in passenger service hauling such trains as the Santa Fe Railway’s Super Chief and El Capitan.
The F7 was the fourth model in GM-EMD’s successful line of F unit locomotives, and by far the best-selling cab unit of all time. In fact, more F7’s were built than all other F units combined. 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.
The F7 differed from the F3, primarily in internal equipment (mostly electrical) and some external features. Its continuous tractive effort rating was 20% higher (e.g. 40,000 lb (18,000 kg) for an F7 with 65 mph (105 km/h) gearing, compared to 32,500 lb (14,700 kg) for an F3 with the same gearing.
A total of 2,366 cab-equipped lead A units and 1,483 cabless-booster or B units were built. (Note: the B unit is often referred to as an “F7B”, whereas the A unit is simply an “F7”.)
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, F units 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’s prime mover is a 16-cylinder 567B series Diesel engine developing 1,500 hp (1.1 MW) at 800 rpm. The 567B is a mechanically aspirated two-stroke design in a 45 degree Vee configuration, with 567 cu in (9.29 L) displacement per cylinder, for a total of 9,072 cu in (148.66 L). A direct current generator that is mechanically coupled to the flywheel end of the engine powers four traction motors, with two motors mounted on each Blomberg B truck. EMD has built all of its major components since 1939
The Evolution Series is a line of diesel locomotives built by GE Transportation Systems, initially designed to meet the U.S. EPA’s Tier 2 locomotive emissions standards that took effect in 2005. The first pre-production units were built in 2003. Evolution Series locomotives are equipped with either AC or DC traction motors, depending on the customer’s preference. All are powered by the GE GEVO engine.
The Evolution Series was named as one of the “10 Locomotives That Changed Railroading” by industry publication Trains Magazine. It was the only locomotive introduced after 1972 to be included in that list.
Currently, four different Evolution Series models have been produced for the North American market. They are all six axle locomotives and have the wheel arrangement C-C (AAR classification) or Co’Co’ (UIC classification), except for the ES44C4 which has an A1A-A1A wheel arrangement. All North American Evolution Series locomotives are equipped from the factory with a Nathan-Airchime K5HL-R2 “Evolution” airhorn, and most later models are equipped with a Graham-White 373 (electronic) E-BELL.
The ES40DC (Evolution Series, 4000 HP, DC traction) replaced the Dash 9-40CW model in GE’s range and, like the former model, was delivered exclusively to Norfolk Southern Railway. ES44DC’s owned by CSX Transportation were also given this designation after being de-rated to 4,000 hp (3,000 kW). As of 2014, all of Norfolk Southern’s ES40DCs have been uprated to 4,400 horsepower (3,300 kW), making them ES44DCs.
The ES44DC (Evolution Series, 4400 HP, DC traction) replaces the Dash 9-44CW model in GE’s range. Primary users are BNSF Railway, CSX Transportation, and Canadian National Railway. Pilbara Iron in Australia ordered a lengthened, international version designated ES44DCi. The extra length is used for a larger radiator to increase cooling capacity in the Australian outback.