Bombardier–Alstom HHP-8

The Bombardier–Alstom HHP-8 (High Horse Power 8000) is a type of twin-cab electric locomotive manufactured by a consortium of Bombardier Transportation and Alstom for Amtrak and MARC. The locomotive's electrical drive technology is directly derived from the SNCF BB 36000 manufactured by Alstom.

Bombardier–Alstom HHP-8
MARC No. 4915 at Odenton in 2014
Type and origin
Power typeElectric
BuilderBombardier Transportation, Alstom[1]
Total producedAmtrak: 15
Gauge1,435 mm (4 ft 8 12 in) standard gauge
Wheel diameter40 in (1,016 mm)
Minimum curve76 m (249.34 ft)
Wheelbase9 ft 4 in (2.84 m)
  Truck35 ft 3 in (10.74 m)
Length67 ft 1 in (20.45 m) over couplers
Width10 ft 4 in (3.15 m)
Height14 ft 2 in (4.32 m)
Loco weight222,000 lb (101 t)
Power supplyCatenary
Electric system/s
  • 12 kV 25 Hz AC
  • 12.5 kV 60 Hz AC
  • 25 kV 60 Hz AC
Current pickup(s)Dual pantographs
Traction motors4 × 1.5 MW (2,000 hp) Alstom 4-FXA-4559C
Loco brake
  • Electrical : regenerative and rheostatic brakes
  • Friction : two disc brakes per axle
Safety systemsCab signals, ACSES
Performance figures
Maximum speed135 mph (217 km/h)
Power output6,000 kW (8,000 hp) continuous
Tractive effort:
  Starting71,240 lbf (316.9 kN)
  Continuous56,200 lbf (250.0 kN)
  • Amtrak: 680-694 (formerly 650-664)
  • MARC: 4910-4915
Official nameHSEL (High Speed Electric Locomotive)[2]
Sources:[3] except where noted

A small class size and reliability problems with correspondingly high per capita maintenance and replacement costs led Amtrak to retire all of its HHP-8s after only a decade in service. MARC initially made the decision to retire their HHP-8s, but later opted to refurbish their fleet from 2017-2018.


Amtrak assumed control of almost all private sector intercity passenger rail service in the United States on May 1, 1971. The centerpiece of Amtrak's system was the Northeast Corridor, a 457-mile (735 km) line between Washington, D.C. and Boston, Massachusetts, via New York City. The line was electrified from Washington through New York to New Haven, Connecticut; diesel locomotives handled trains over the remaining 157 miles (253 km) between New Haven and Boston. In the 1990s Amtrak rebuilt and electrified the route as part of the project which established high-speed Acela Express service between Washington and Boston. The elimination of diesel service between New Haven and Boston meant that Amtrak would need additional electric locomotives to pull conventional trains east of New Haven. Neither of Amtrak's existing designs, the EMD AEM-7 and GE E60, were still in production, and the latter was slated for retirement. Amtrak chose to have Bombardier and Alstom, makers of the Acela Express, produce a visually-similar derivative for conventional service.[4][5]


The HHP-8 measures 67 feet 1 inch (20.45 m) long by 10 feet 4 inches (3.15 m) wide and stands 14 feet 2 inches (4.32 m) tall (from the rail to the locomotive roof, excluding the pantographs). This was 16 feet (4.9 m) longer than the AEM-7, though still shorter than the E60. The locomotive weighs 220,000 pounds (100,000 kg). The carbody is stainless steel; the locomotive has a 6 MJ crash energy absorbance structure.[3]

Reflecting the varied electrification schemes on the Northeast Corridor the locomotives were designed to operate at three different voltages: 12 kV 25 Hz AC, 12.5 kV 60 Hz AC, and 25 kV 60 Hz AC. The electrical traction system is directly derived from the system used on Alstom's BB 36000 Astride locomotives;[6] this includes four 1.5 megawatts (2,000 hp) three phase asynchronous traction motors powered by GTO based inverters, with one inverter per motor; the electric system also allows regenerative and rheostatic braking.[3] The locomotives were designed for up to 135 mph (217 km/h) operation but are actually limited in service to FRA Tier 1 standards, operating up to 125 mph (201 km/h).[3][7]


The Acela and the HHP-8
The visual similarity between the HHP-8 (top) and Acela Express (bottom) was a deliberate design choice.

Amtrak ordered 15 HHP-8s in 1996 at the same time as its Acela Express trainsets. The HHP-8s have external styling that is similar to the Acela trainsets, but are designed to operate as independent locomotives, hauling conventional passenger rolling stock. The units supplemented the EMD AEM-7s and allowed Amtrak to commence retirement of the GE E60.[1][8] Amtrak did not purchase the locomotives outright but leased them from Philip Morris Capital.[9]

The locomotive's original type designation was HHL-8, for "High Horsepower Locomotive, 8,000 (nominal) horsepower".[10] This was subsequently changed to HHP-8.

In conjunction with the Amtrak order, MARC also acquired six HHP-8s,[7] which MARC uses on their Penn Line service along the Northeast Corridor between Perryville and Washington, DC.

Amtrak operated its HHP-8s on the Northeast Corridor between Boston and Washington, DC;[11] racking up approximately 1,000,000 miles each in service (based on 2009 figure).[12]

In 2002, Amtrak's fleet of 15 units was temporarily withdrawn along with the Acela Express trains due to cracks in components of the trucks.[13][14]

Amtrak retirement

Amtrak's HHP-8s suffered from low reliability. As a result, after only one decade in service, their replacement was considered, concurrent with the replacement of the older AEM-7 locomotive fleet, since a large order for a standardized fleet would have price economies, and the resultant fleet would have lower overall maintenance costs. A replacement fleet of 70 locomotives starting delivery in 2012 was planned, with HHP-8s kept as a reserve in the short term.[12]

In October 2010, Amtrak ordered 70 Siemens ACS-64 locomotives to replace both the HHP-8 and the older AEM-7 locomotives, with deliveries beginning in early 2013.[15] Amtrak retired its last HHP-8 on November 7, 2014. All units are now stored; to avoid duplicate numbering with ACS-64 units 650–664, Amtrak renumbered its retired HHP-8s to 680–694.[16] Philip Morris sued Amtrak in 2019, alleging that Amtrak had cannibalized eight of the fifteen locomotives for parts, in violation of the terms of the lease.[17]

MARC Refurbishment

While reports in 2016 indicated that MARC planned to retire their HHP-8 locomotives and replace them with Siemens SC-44 Charger locomotives,[18] MARC instead started a refurbishment program for its HHP-8s in 2017.[19] Issues with equipment cooling that kept the HHP-8 locomotives from properly working were addressed.

As of September 2017, the first HHP-8 reconditioned under this program had been delivered and was undergoing successful testing.[20]

As of March 2018, the first HHP-8 reconditioned was running for three weeks without major issue (a software issue was corrected in this time). A second HHP-8 was being reconditioned.[21]

As of June 2018, The second HHP-8 had the most unreliable power control components replaced and was back in service. The remainder of the upgrade on this locomotive was to be done by the end of 2018. MARC planned to upgrade the remaining HHP-8 locomotives in their fleet.[22]

Named units

There is only one HHP-8 that is named. MARC unit #4913 is named "Kathryn D. Waters" a former administrator of the Maryland Transit Administration.[23]


  1. Cudahy, Brian J. (2002), Rails Under the Mighty Hudson (2nd ed.), New York: Fordham University Press, pp. 89–90, ISBN 978-0-82890-257-1, OCLC 911046235
  2. McDonnell, Greg (2015). Locomotives: The Modern Diesel and Electric Reference (2nd ed.). Richmond Hill, Ontario: Boston Mills Press. p. 264. ISBN 978-1-77085-609-7.
  3. "APPENDIX 5 : Design Data : High Horsepower Electric Locomotive (for Amtrak, MARC)" (PDF). Bombardier Transportation.
  4. Cudahy 2002, p. 89
  5. "Building the Infrastructure for Acela Express". History Blog. February 25, 2016.
  6. Allenbach, Jean-Marc; Chapas, Pierre; Comtel, Michel; Kaller, Roger (2008), Traction électrique (in French), 1, Presses polytechniques et universitaires romandes, p. 328, ISBN 978-2-88074-674-2, La partie électrique de locomotives américaines (25 Hz/60 Hz) - 15 HHP-8 (AME 125) pour l'Amtrak et 6 pour le Maryland - est aussi directement dérivée
  7. "Caltrain Electrification Project" (PDF),, Section 4: ELECTRIC ROLLING STOCK EQUIPMENT POWER, High Horsepower Amtrak/MARC Locomotive, August 2000
  8. Simon, Elbert; Warner, David C. (2011). Amtrak by the numbers: a comprehensive passenger car and motive power roster, 1971-2011. Kansas City, Missouri: White River Productions. p. 68. ISBN 978-1-932804-12-6.
  9. Amtrak Office of the Inspector General (July 21, 2009). "Lessons Learned: An Analysis of the Acela and Surfliner Programs" (PDF).
  10. "From GG1 to E60 to AEM7 to HHL-8". Trains Magazine. September 1999.
  11. Loomis, Jim (November 24, 2011). All Aboard: The Complete North American Train Travel Guide. Chicago Review Press. p. 140. ISBN 9781569768495.
  12. "Amtrak Fleet Strategy : Building a Sustainable Fleet for the Future of America's Intercity and High-Speed Passenger Railroad" (PDF). February 2010. pp. 17, 21, 24, 37, 42.
  13. Wald, Matthew L. (August 16, 2002). "Amtrak sideline more locomotives because of defect". The New York Times.
  14. Phillips, Don (August 16, 2002). "High-Speed Trains Shut Down Again". The Washington Post. Retrieved March 10, 2018.
  15. "Siemens AG bags $466-mn order from US railroad company Amtrak". October 29, 2010. Retrieved November 4, 2013.
  16. "Amtrak City Sprinter Class ACS64 Electric Locomotive For Amtrak's North East Corridor (NEC) High Speed Passenger Service" (PDF). Siemens AG Infrastructure & Cities Sector Rail Systems Division. Retrieved December 24, 2013.
  17. Vantuono, William C. (November 11, 2019). "HHP-8 "Cannibalization" Generates Lawsuit". Railway Age.
  18. Vantuono, William C. "MARC replacing electric locomotive fleet with high-speed diesels". Retrieved September 11, 2016.
  19. "MARC Riders Advisory Council Meeting Minutes: April 20, 2017" (PDF). MTA Maryland. April 20, 2017.
  20. "MARC Riders Advisory Council Meeting Minutes: September 21, 2017" (PDF). MTA Maryland. September 21, 2017.
  21. "March 15, 2018 Minutes" (PDF). MTA Maryland. March 15, 2018.
  22. "June 21, 2018 Minutes" (PDF). MTA Maryland. June 21, 2018.
  23. t55z (September 12, 2013), MARC HHP-8 4913 "Kathryn D. Waters", retrieved July 29, 2019
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