F40PH-2 locomotive

EMD F40PH
Amtrak F40PHR No. 315 on the eastbound California Zephyr at Tunnel No. 17 near Newcastle, California in 1995
Type and origin Power type Diesel-electric Builder GM Electro-Motive Division (EMD) General Motors Diesel (GMD) Build date 1975–1992 (EMD) 1988–1998 (MK / MPI) Total produced 506
Specifications Configuration: ​  • AAR B-B Gauge 4 ft 8 1⁄2 in (1,435 mm) Trucks Blomberg M Length 56 ft 2 in (17.1 m) Loco weight 260,000–282,000 lb (117,934–127,913 kg) Prime mover EMD 645E3 Engine type V16 Diesel Alternator AR10/D14 Traction motors D77 Cylinders 16
Performance figures Maximum speed 103–110 mph (166–177 km/h) Power output 3,000–3,200 hp (2.2–2.4 MW)

The EMD F40PH is a four-axle 3,000–3,200 hp (2.2–2.4 MW) B-B diesel-electric locomotive built by General Motors Electro-Motive Division in several variants from 1975 to 1992. Intended for use on Amtrak's short-haul passenger routes, it became the backbone of Amtrak's diesel fleet after the failure of the EMD SDP40F. The F40PH also found widespread use on commuter railroads in the United States and with Via Rail Canada. Additional F40PH variants were remanufactured from older locomotives by Morrison-Knudsen and MotivePower Industries between 1988–1998.

Amtrak retired its fleet of F40PHs in the mid-1990s in favor of the GE Genesis, but the locomotive remains the mainstay of Via Rail's long-distance trains and is a common sight on many other commuter railroads throughout the United States. In addition, Amtrak has kept a number of de-engined F40PHs in use as Cabbage cars/Non-Powered Control Units.

Amtrak inherited an aging and mechanically-incompatible fleet of diesel locomotives from various private railroads on its startup in 1971. The most modern locomotives remained in private hands to operate the various commuter services which, by law, did not pass to Amtrak. To replace these Amtrak ordered 150 EMD SDP40F locomotives, which began entering service in 1973. These were supplemented by 25 GE P30CHs which entered service in 1975. The SDP40F was a troubled design; problems with weight distribution led to a series of derailments in the mid-1970s. Meanwhile, the poor truck design of the P30CH (and the electric GE E60CP) curtailed further orders of that unit when Amtrak found itself needing more short- and medium-distance power in the spring of 1975.