The General Motors Electro-Motive Division model F40PH is a 4-axle 3000 horsepower diesel-electric locomotive intended for passenger service. The locomotive was built from 1976 onwards.
The locomotive’s introduction was spurred as a replacement for the EMD SDP40F type, Amtrak’s first series of locomotives built new for them since inception in 1971. Problems with the SDP40F led to the introduction of the F40PH, based on the proven EMD GP40 series freight locomotives using a two axle truck of known reliability.
The F40PH was also purchased by a number commuter railroads, including Metra, Tri-Rail, CalTrain and Metrolink, all of which still operate the locomotives.
The F40PH is equipped with a turbocharged EMD 645E3 16 cylinder, two-stroke, water-cooled “Vee” diesel engine (prime mover) that develops 3,000 tractive horsepower at maximum rpm. The main (traction) generator converts mechanical energy from the prime mover into electricity that is distributed through a high voltage cabinet to the traction motors.
The four traction motors are directly geared to a pair of driving wheels. The gear ratio of the traction motors to wheel axle determines the maximum operating speed of the locomotive; a standard F40PH has a gear ratio of 57:20 which provides a top speed of 103 mph.
In later years, as Amtrak’s F40PH fleet was being replaced by the newer GE Genesis-series locomotives, Amtrak converted a number of the retired units — generally ones with major mechanical problems limiting their value in the resale or lease marketplace — into “Non-Power Control Unit” cab cars.
Commonly known as “Cabbages,” a portmanteau of “cab” and “baggage,” the units had their prime movers and traction motors removed, and a large roll-up door installed in the side, allowing the former engine compartment to be used for baggage. The units were renumbered into Amtrak’s car-series numbers by adding “90” before the former locomotive number.