According to Wikipedia - First built in 1994, the locomotive is a 3,200 hp (2.4 MW) B-B diesel-electric locomotive intended for service on North American mainlines.[2] This locomotive is equipped with a turbocharged EMD 12-710G3C-EC, a 12 cylinder, 2 stroke diesel engine (prime mover). The main (traction) alternator converts mechanical energy from the prime mover into electrical energy that is distributed through a high voltage cabinet to direct current traction motors. Each of the four traction motors is directly geared to a pair of driving wheels. The gear ratio of the traction motors (model D87BTR) to wheel axle determines the maximum operating speed of the locomotive; a standard F59PHI has a gear ratio of 56:21 which provides a top speed of 110 mph (176 km/h).

The F59PHI has a fully enclosed carbody which provides protected walkways for easy access to the engine room and trailing units. This arrangement allows routine maintenance while the locomotive is in service. The noteworthy aspect of this locomotive's exterior is the use of composites to present a streamlined appearance.[2]

To supply electrical power for passenger service, the F59PHI is equipped with a secondary electrical generator referred to as the Head End Power (HEP) unit. The head-end generator generates AC power at 480 V, 60 Hz AC, and can be rated between 500 and 750 kW to provide power to the passenger carriages for lighting, electric heating, and air conditioning. The head-end generator is powered by a second diesel engine dedicated to it. With this arrangement, the prime mover is not burdened by head-end power generation and consequently is used solely for supplying tractive effort.

When it debuted for Caltrans in late 1994, the F59PHI was the first locomotive in the United States which met California's stringent emission standards.[2]

Examples of the F59PHI are currently operated by these companies:

AMT (Montreal)
Amtrak (Amtrak Cascades, all Amtrak California routes, Coast Starlight, and Piedmont)
Metrolink (Southern California)
North County Transit District (with the San Diego Coaster)
Sound Transit (Sounder Commuter Rail)
Trinity Railway Express
West Coast Express