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MPXpress is a series of diesel-electric passenger train locomotives designed for commuter rail service. The locomotives are built by MotivePower, a subsidiary of Wabtec. To date, MPI has offered five main variants: MP36PH-3S, MP36PH-3C, MP40PH-3C, MP32PH-Q, and MP54AC. However, due to federal emissions standards, the MP54AC is the only locomotive currently for sale in the United States, as it is the only MPXpress locomotive that meets Tier 4 standards.

MPI MPXpress
New Mexico Rail Runner MP36PH-3C in New Mexico
Type and origin
Power typeDiesel-electric
Build date2003–present
Total produced217 (+26 on order):
  • MP36PH-3S: 27
  • MP36PH-3C: 110
  • MP40PH-3C: 70
  • MP32PH-Q: 11
  • MP54AC: 1 (26)
Number rebuiltMP36PH-3S: 11 (to MP36PH-3C)
MP40PH-3C: 1 (to MP54AC)
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Wheel diameter3 ft 4 in (1,020 mm)
Minimum curve248 ft (76,000 mm)
Wheelbase9 ft 0 in (2,740 mm) (original)
9 ft 4 in (2,840 mm) (new)
Length68 ft (20.73 m)
Width10 ft 7.5 in (3,238 mm)
Height15 ft 6 in (4,720 mm)
Loco weight285,000 to 295,000 lb (129,000 to 134,000 kg)
Prime moverEMD 16-645F3B (MP36PH-3S, MP36PH-3C)
EMD 16-710G3B-T2 (MP40PH-3C)
EMD 16-645E3C (MP32PH-Q)
(2x) Cummins QSK60 (MP54AC)
Performance figures
Maximum speed82–102 mph (132–164 km/h) (MP36PH-3C, MP32PH-Q)
93 mph (150 km/h) (MP40PH-3C)
110 mph (180 km/h) (MP54AC)
Power output3,600 hp (2,700 kW) (MP36PH-3S, MP36PH-3C)
4,000 hp (3,000 kW) (MP40PH-3C)
3,000 hp (2,200 kW) (MP32PH-Q)
5,400 hp (4,000 kW) (MP54AC)
Tractive effort72,500–85,000 lbf (322–378 kN) (MP36PH-3C, MP36PH-3S)

85,000 lbf (380 kN) (MP40PH-3C)[1]

70,000 lbf (310 kN) (MP32PH-Q)
82,900 lbf (369 kN) (MP54AC)
OperatorsSee list

The MPXpress line of locomotives were the first production passenger locomotives to meet FRA safety regulations regarding crashworthiness and fire safety. The line also meets APTA crashworthiness standards.

Production of the locomotives have kept pace with increasingly stringent emissions regulations from the United States Environmental Protection Agency (EPA). Between 2002 and 2015, the EPA has issued four "tiers" of emissions standards and in each case the MPXpress was the first (and in some cases, only) passenger locomotive to meet the standard.

Numerous public transit agencies in Canada and the United States have ordered MPXpress locomotives for their commuter rail services. GO Transit is currently the largest client for MPI MPXpress locomotives, with 67 in their fleet and an additional 18 on order.




A Metra MP36PH-3S in Blue Island. Metra is the only railroad that ordered this model.

The MP36PH-3S uses a 16-cylinder EMD 645F3B diesel engine as its prime mover, capable of generating 3,600 hp. Head-end power (HEP) is generated by a static inverter that receives its power through connections to the prime mover (hence the "S" (static) designation). Compared to a locomotive with a separate HEP generator, the prime mover must constantly maintain a higher RPM in order to supply power to the passenger cars. The setup is simpler but leads to higher noise levels and higher fuel consumption.

When providing the maximum 500 kW HEP load, maximum traction power is reduced to 2,930 hp since HEP generation diverts some power from the prime mover.[2]

The MP36PH-3S was the first variety of MPXpress locomotive to be built and the launch customer was Metra, a commuter railroad in the Chicago area. Metra ordered 27 of these locomotives in 2001, which were built and delivered between 2003 and 2004. Fourteen were to replace the railroad's aged F40C fleet, while the rest were for fleet expansion. Metra is currently the only operator of the MP36PH-3S variant of the MPXpress.

When the locomotives were first delivered, the onboard computer systems proved problematic. At one point in 2004, because Metra had so many MPXpress locomotives out of service, two F40Cs had to be placed back into service for a short time.

Conversion to MP36PH-3C specificationEdit

Starting in 2015, Metra is converting its MP36PH-3S locomotives to the MP36PH-3C specification by removing the static inverter and replacing it with a separate HEP generator. This is being done in an effort to reduce noise pollution and boost fuel efficiency. Metra's MP36PH-3C locomotives all have extended radiators to supply the extra cooling for the new Caterpillar generators. Locomotive No. 417 was the first one to be converted and was sent to MPI in Boise. The following units are being converted in-house at Metra's 47th Street shops on the South Side of Chicago.


An MP36PH-3C in Caltrain livery. Nine railroads operate this model, with Caltrain being the launch customer.

The MP36PH-3C has the same EMD 645F3B prime mover as the MP36PH-3S model, but with a separate head-end power generator, a Caterpillar C-27[3] diesel engine (hence the "C" designation). In this arrangement, when providing HEP, the full 3,600 hp from the prime mover is available for traction, and the prime mover is allowed to idle at a lower RPM. Having two engines is more complex, but results in lowered noise emissions and lower fuel consumption.

The launch customer for the MP36PH-3C was Caltrain, a commuter railroad in the San Francisco Bay Area. Caltrain ordered 6 of these locomotives in 2003, which were built and delivered that same year. This locomotive has gone on to become the most popular MPXpress variant, with 100 delivered to nine different customers.


An MP40PH-3C in the old GO Transit livery. GO Transit and Sounder Commuter Rail operate this model.

The MP40PH-3C introduced a new prime mover, the larger 16-cylinder EMD 710GB series diesel engine, capable of generating 4,000 hp. The MP40PH-3C also uses an EMD alternator and traction motors.

The launch customer for the MP40PH-3C was GO Transit, a commuter railroad in the Toronto area. The MP40PH-3C was developed in response to a bid request from GO Transit for locomotives capable of generating 4,000 hp, hauling 12 passenger cars and traveling at speeds up to 93 mph (150 km/h). MotivePower and GE Transportation responded to the request, with MotivePower being selected as the winning bidder. GO Transit placed an order for 27 locomotives in 2006, which were built and delivered between 2007 and 2008.

In 2011, MotivePower upgraded the MP40PH-3C to comply with the EPA's more stringent Tier 3 emissions standard,[4][5] which was in effect between 2012 and 2014. Three locomotives meeting this standard were built, all delivered to Sounder commuter rail in the Seattle area. Ten additional locomotives for GO Transit are also Tier 3 compliant.


An MPI MP32PH-Q locomotive in SunRail livery. Sunrail is the only operator of the MP32PH-Q.

The MP32PH-Q was built from 2013 to 2014 for SunRail. They have similar specifications as new MPXpress locomotives, but are rebuilt and refurbished from units that had previously operated on MARC as GP40WH-2 locomotives. Inside the locomotive, the 3,000 hp EMD 16-645E3C prime mover has been rebuilt and electronics have been upgraded using the same equipment as other MPXpress locomotives. On the exterior, the MP32PH-Q retains the hood unit layout of the former GP40WH-2, but a new four-window MPXpress cab replaces the original cab.[4][6]


An MPI MP54AC locomotive in the new GO Transit livery. GO Transit is the launch customer of this model.

The MP54AC (also known as MP40PHTC-T4AC)[7] is the latest locomotive in the MPXpress family and the only model available for sale in the US. It is designed to both meet the EPA's stringent Tier 4 emissions standard and offer higher performance than the MP40PH-3C. The MP54AC uses a pair of Cummins 16-cylinder QSK60 engines rated at 2,700 hp each (5,400 hp total), which qualifies it as the most powerful diesel-electric passenger locomotive in North America, both currently and historically (The 8600 hp Siemens ACS-64, an electric locomotive, is the most powerful passenger locomotive overall). During periods of low power demand, the locomotive can operate on just one engine to reduce noise pollution and boost fuel efficiency. Currently, the MP54AC can be built as new or by having existing MPXpress locomotives rebuilt to the standard.[8]

The locomotive competes with the EMD F125 and Siemens Charger. Both the MP54AC and F125 have struggled to find customers, unlike the Charger series which has secured several major contracts from multiple railroads.

GO Transit was the launch customer for the MP54AC. The first prototype unit was built by converting a MP40PH-3C owned by GO Transit (unit 647). MotivePower removed the EMD prime mover and HEP motor and replaced them with the twin Cummins engines. Heavy modifications were made to the body to accommodate extra air intake and exhaust stacks.[9][10] Unit 647 was delivered to GO Transit late 2015 and was seen under testing on December 12, 2015.[11]

Initially GO Transit had planned to convert a total of ten MP40PH-3Cs to the new MP54AC standard; it later ordered 16 additional newly built MP54AC locomotives[12] and eventually converted the order for rebuilt units to new builds for a total of 26.[13] The MP54ACs are also planned to replace the remaining F59PH locomotives left on the roster.[14]


Internal LayoutEdit

Cutaway drawing of New Mexico's RailRunner MPI MP36PH-3C. This layout varies for other locomotives.


  1. ^ "LOS ANGELES COUNTY METROPOLITAN TRANSPORTATION AUTHORITY: Diesel Multiple Unit (DMU) Technical Feasibility Analysis" (PDF). LTK Engineering Services. May 4, 2009. Retrieved September 7, 2014.
  2. ^ "Locomotives". LTK Engineering Services. Archived from the original on September 8, 2014.
  3. ^ Lex, Robert (29 September 2013). "Northstar Commuter Rail MP36PH-3C Parts". Parts List for MPXpress locomotives.
  4. ^ a b "SunRail, Sound Transit order MotivePower locomotives". Trains. September 12, 2011. Retrieved September 13, 2011.
  5. ^ "Archived copy" (PDF). Archived from the original (PDF) on April 15, 2012. Retrieved November 3, 2011.CS1 maint: Archived copy as title (link)
  6. ^ Murdock, Ken (April 2014). "Winter Park's Station Dedication" (PDF). The Flatwheel. 3–5. Archived from the original (PDF) on September 8, 2014.
  7. ^ "MotivePower Tier 4 diesel delivered to Go Transit". International Railway Journal. 16 March 2018. Retrieved 16 March 2018.
  8. ^ "MP54 AC Commuter Locomotive | Wabtec Corporation". Retrieved 2016-11-28.
  9. ^ "MP54 AC COMMUTER LOCOMOTIVE". Wabtec Corporation. Retrieved 2015-12-16.
  10. ^ "MP54AC" (PDF). Wabtec. Archived from the original (PDF) on December 17, 2015.
  11. ^ "First MP54AC testing on GO Transit". Railway Age. Retrieved 2015-12-16.
  12. ^ "Prototype MP54AC delivered to Metrolinx, GO Transit". Railway Age. 2 March 2016. Retrieved 16 March 2018.
  13. ^
  14. ^

External linksEdit