EMD F125 Spirit

The EMD F125 Spirit is a passenger diesel locomotive developed by Electro-Motive Diesel for the North American commuter rail market, representing the manufacturer's first new passenger locomotive offering for that market in roughly fifteen years. The gap since EMD's previous passenger designs, the DE30AC and DM30AC built for the Long Island Rail Road, underscored how thoroughly the passenger locomotive segment had been ceded to competitors during the intervening period. Metrolink, the commuter rail agency serving the greater Los Angeles region, became the sole customer for the type, signing a base order on May 31, 2013, for ten locomotives with options for additional units, with the total cost of an initial tranche estimated at approximately 150 million dollars. Development and delivery of the F125 proved substantially more difficult than anticipated. The first example began testing in early 2016 and was publicly unveiled at Los Angeles Union Station on July 18, 2016, with its first mainline revenue run following on June 10, 2017. However, technical difficulties significantly impeded acceptance, and by November 2018 Metrolink had accepted only five of the ordered locomotives, placing the program approximately two years behind schedule. The full complement of ordered units was eventually delivered and placed into service by 2022, where they replaced earlier EMD F59PH and F59PHI locomotives that had long formed the backbone of Metrolink's motive power fleet. The F125 entered a competitive marketplace alongside other Tier 4 compliant passenger locomotives, most notably the Siemens Charger series, which proved considerably more successful commercially and accumulated orders exceeding 450 units from operators including Amtrak and Via Rail. The F125 and the MPI MP54AC both struggled to attract customers beyond their initial buyers, limiting the Spirit's broader market impact and leaving Metrolink as the type's only operator.

The F125 Spirit is configured as a four-axle locomotive riding on a B-B wheel arrangement and is powered by a Caterpillar C175-20 twenty-cylinder diesel engine producing 4,700 horsepower. It employs AC traction motors and is designed for a maximum in-service speed of 125 miles per hour, a figure reflected in the locomotive's model designation, with the capability to haul consists of up to ten passenger cars. The locomotive meets EPA Tier 4 emissions standards through the use of exhaust aftertreatment systems, placing it among the cleanest diesel passenger locomotives built for the North American market. Additional engineering features include extended-range blended and dynamic braking with head-end power regeneration capabilities and advanced crash energy management technology intended to improve occupant protection in collision scenarios. The exterior styling of the F125 was designed by Vossloh of Spain, giving the locomotive a streamlined appearance notably different from earlier EMD passenger products. The incorporation of a foreign industrial design firm reflected broader trends in locomotive aesthetics during the period, as manufacturers sought to differentiate their products visually while meeting increasingly stringent structural and safety requirements. The combination of AC traction, high top speed, and Tier 4 compliance represented a significant technical departure from the F59 series locomotives the F125 was intended to replace, though the program's troubled acceptance process demonstrated the challenges inherent in introducing a complex new design into demanding revenue service conditions.

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