EMD FP7

EMD FP7

AMTK #113 leading two EMD SDP40Fs with the San Francisco Zephyr at Yuba Gap, 1975.

Type and origin Power type Diesel-electric Builder General Motors Electro-Motive Division (EMD) General Motors Diesel (GMD, Canada) Model FP7 Build date June 1949 – December 1953 Total produced 381

Specifications AAR wheel arr. B-B Gauge 4 ft 8 1⁄2 in (1,435 mm) Trucks Blomberg B Wheel diameter 40 in (1,016 mm) Minimum curve 23° (250.79 ft or 76.44 m radius) Wheelbase 43 ft (13.11 m) Length 55 ft 2 1⁄4 in (16.82 m) Width 10 ft 8 in (3.25 m) Height 15 ft (4.57 m) Loco weight 260,000 lb (120,000 kg) Fuel capacity 1,200 US gal (4,500 L; 1,000 imp gal) Prime mover EMD 567B RPM range 800 Engine type Two-stroke V16 diesel Aspiration Roots-type supercharger Generator EMD D-12 Traction motors (4) EMD D-27-B Cylinders 16 Cylinder size 8 1⁄2 in × 10 in (216 mm × 254 mm)

Performance figures Maximum speed 100–119 mph (161–192 km/h) Power output 1,500 horsepower (1,100 kW)

Career Locale North America, Saudi Arabia

The EMD FP7 was a 1,500 horsepower (1,100 kW), B-B dual-service passenger and freight-hauling diesel locomotive produced between June 1949 and December 1953 by General Motors' Electro-Motive Division and General Motors Diesel. Final assembly was at GM-EMD's La Grange, Illinois plant, excepting locomotives destined for Canada, in which case final assembly was at GMD's plant in London, Ontario. The FP7 was essentially EMD's F7A locomotive extended by four feet to give greater water capacity for the steam generator for heating passenger trains.

While EMD's E-units were successful passenger engines, their A1A-A1A wheel arrangement made them less useful in mountainous terrain. Several railroads had tried EMD's F3 in passenger service, but there was insufficient water capacity in an A-unit fitted with dynamic brakes. The Atchison, Topeka and Santa Fe Railway's solution was to replace the steam generators in A-units with a water tank, and so only fitted steam generators into the B-units. The Northern Pacific Railway's solution was to fit extra water tanks into the first baggage car, and to pipe the water to the engines. The real breakthrough came when EMD recognized the problem and added the stretched FP7 to its catalog.

A total of 381 cab-equipped lead A units were built; unlike the freight series, no cabless booster B units were sold. Regular F7B units were sometimes used with FP7 A units, since they, lacking cabs, had more room for water and steam generators. The FP7 and its successor, the FP9, were offshoots of GM-EMD's highly successful F-unit series of cab unit freight diesels.