EMD F125
SCAX 905, the first F125 delivered to Metrolink, on display at Los Angeles Union Station
Type and origin
Power typeDiesel-electric
BuilderElectro-Motive Diesel (EMD)
Build date2015–2021
Total produced40
 • UICBo′Bo′
Gauge4 ft 8+12 in (1,435 mm)
Wheel diameter40 in (1,016 mm) (New)
Minimum curve250 ft (76 m) radius/ 23°
WheelbaseLocomotive: 42 ft 4 in (12.90 m) (between truck centers)
Truck: 9 ft 7 in (2.92 m)
Length69 ft 0 in (21.03 m)
Width10 ft 0 in (3.05 m)
Height14 ft 6+12 in (4.432 m)
Axle load71,250 lb (32,318 kg)
Adhesive weight100%
Loco weight285,000 lb (129,274 kg) (Nominal)
Fuel typeDiesel
Fuel capacity2,350 US gal (8,900 L; 1,960 imp gal)
Lubricant cap.180 US gal (680 L; 150 imp gal)
Coolant cap.291 US gal (1,100 L; 242 imp gal)
Sandbox cap.Four boxes
@ 6.25 cu ft (177 L) each
Prime moverCaterpillar C175-20
RPM range800-1,800
Engine type45° V20, four stroke cycle
Displacement105.8 L (6,460 cu in)[1]
AlternatorKato AK30-8
Traction motorsEMD AC Traction Motors, model A2921-5
1,000 hp (750 kW) each
Cylinder size5.29 L (323 cu in)
MU workingYes
Train heatingLocomotive supplied Head end power (inverters rated between 600-1000 kW)
Loco brakeDynamic / Regenerative / Electropneumatic / Blend Brake
Safety systemsI-ETMS positive train control
Performance figures
Maximum speed125 mph (201 km/h) (Optional)
100 mph (160 km/h) (79:22 gear ratio)
Power outputAt Alternator: 4,560 hp (3,400 kW)
At Wheels: 4,000 hp (3,000 kW) max
Tractive effortStarting: 71,000 lbf (316 kN)
Continuous: 47,000 lbf (209 kN) @ 32 mph (51 km/h)
Factor of adh.4.014
Brakeforce47,200 lbf (210 kN) from 20 mph (32 km/h) to 1 mph (1.6 km/h)
OperatorsMetrolink (California)
Number in class40

The EMD F125 "Spirit" is a four-axle passenger diesel locomotive manufactured by Electro-Motive Diesel (EMD) for the North American market since 2015. It is powered by a Caterpillar C175-20 V20 diesel engine rated at 4,700 hp (3,500 kW). The locomotive is capable of traveling at a maximum in-service speed of 125 mph (201 km/h) pulling consists of up to 10 cars. It was EMD's first new passenger locomotive for the North American market in 15 years, with the most recent predecessor passenger locomotive being the EMD DE30AC and DM30AC built for the Long Island Rail Road. So far, Metrolink is the only customer of the F125.

Features of the F125 include Tier 4 emissions compliance (with exhaust after-treatment), AC traction systems, extended-range blend and dynamic brakes with HEP regeneration capabilities, advanced crash energy management (CEM) technology, and a streamlined body design, designed by Vossloh of Spain.[2]


The Los Angeles commuter rail agency Metrolink was the launch customer for the EMD F125, with an order for 40.[3] The cost of the base order of 10 units with an option of additional 10 was estimated at $150 million, with delivery commencing in 2016.[4][5] The base order was signed on May 31, 2013, for 10 locomotives with an option for additional 10, which has since been exercised.[6][7] Additional orders were exercised as funding became available. They replaced the EMD F59PH and F59PHI.

The first locomotive began testing in the first quarter of 2016 and was shown to the public on July 18, 2016, at Los Angeles Union Station during a special event,[8][9] and had its first mainline run on June 10, 2017.

The bulk of the order was expected to be delivered by April 2017, but major problems with the locomotives had prevented their full acceptance by Metrolink.[10][11] In November 2018, Metrolink announced that only five locomotives had been accepted, and the project was two years behind schedule.[12] As of 2022, all F125 locomotives had been delivered to Metrolink and placed in service.[citation needed]

The F125 competes with other Tier 4 compliant locomotives, such as the Siemens Charger series and the MPI MPXpress MP54AC. Both the F125 and MP54AC have struggled to find customers, unlike the Charger series, which has sold more than 350 units including large orders from Amtrak and Via Rail.


  1. ^ "C175-20 Prime Mover Specifications". Caterpillar. 2014. Retrieved May 4, 2021.
  2. ^ a b "Locomotive Capacities and Specifications". EMD. Retrieved June 16, 2017.
  3. ^ "EMD reenters passenger market". Trains. April 2016. p. 18.
  4. ^ Bowen, Douglas John (December 20, 2012). "EMD gets Metrolink Tier 4 locomotive order". Railway Age. Retrieved May 27, 2016.
  5. ^ "Metrolink to buy newest, cleanest locomotives" (Press release). Los Angeles: Metrolink. December 18, 2012. Archived from the original on December 21, 2012. Retrieved December 22, 2012.
  6. ^ "Metrolink orders EMD passenger locomotives". Railway Gazette International. June 1, 2013.
  7. ^ "Metrolink receives critical funding commitments for low-emission Tier 4 locomotives" (Press release). Los Angeles: Metrolink. February 10, 2014.
  8. ^ Templeton, Dan (July 19, 2016). "Metrolink F125 locomotive unveiled in Los Angeles". International Railway Journal. Retrieved December 4, 2017.
  9. ^ "First Metrolink F125 locomotive unveiled in Los Angeles". Railway Age. July 19, 2016. Archived from the original on November 4, 2019.
  10. ^ Jeon, Yena (January 24, 2014). "F125 Tier-4 EMD Status Report". Metrolink. Retrieved May 27, 2016.
  11. ^ "First Metrolink Tier 4 locomotive completed" (Press release). Los Angeles: Metrolink. January 29, 2016.
  12. ^ "Tier 4 Locomotive Update and Delivery Status". June 8, 2020. Retrieved June 29, 2020.