Bombardier–Alstom HHP-8
| Company type | Electric locomotive |
|---|---|
| Industry | Rail transport |
| Founded | 1999 |
| Headquarters | United States |
Area served | Northeast Corridor, United States |
| Products | Electric locomotives |
The Bombardier–Alstom HHP-8 (High Horse Power 8000) is an electric locomotive featuring dual cabs, developed through a collaboration between Bombardier and Alstom for use by Amtrak and MARC. Its electrical architecture is derived from Alstom’s SNCF Class BB 36000 design.
Manufactured in limited quantities, the HHP-8 encountered issues with reliability and incurred substantial maintenance expenses, leading Amtrak to retire its entire fleet after just 15 years of service. Although MARC initially planned to phase out its six units, it ultimately decided to refurbish them during 2017–2018 to prolong their operational lifespan.
Background
On May 1, 1971, Amtrak assumed control over nearly all private intercity passenger rail operations in the United States, focusing its network around the Northeast Corridor, an electrified rail line stretching from Washington, D.C. to New Haven, Connecticut. Diesel locomotives serviced the remaining segment extending to Boston, Massachusetts. During the 1990s, Amtrak undertook a comprehensive rebuild and electrification of the entire route to facilitate high-speed Acela Express service between Washington and Boston. This expansion necessitated new electric locomotives for conventional trains operating east of New Haven, as older models such as the EMD AEM-7 and GE E60 were either out of production or being retired. Consequently, Amtrak commissioned Bombardier and Alstom—manufacturers of the Acela Express—to develop a derivative locomotive suited for standard service.
Design
The HHP-8 measures in length, in width, and in height, with a weight of , constructed with a stainless steel carbody incorporating a 6 MJ crash energy absorption system. It is longer than the AEM-7 but shorter than the E60 model.
Engineered to accommodate the Northeast Corridor’s multiple electrification standards, this locomotive functions under three voltage systems: 25 kV 60 Hz AC between Boston and New Haven; 12.5 kV 60 Hz AC from New Haven to New York; and 12 kV 25 Hz AC from New York to Washington. Its electrical components are based on Alstom’s BB 36000 Astride locomotives, equipped with four three-phase asynchronous traction motors each driven by GTO-based inverters. The system supports both regenerative and rheostatic braking methods. Although engineered for speeds up to , it complies with Federal Railroad Administration Tier 1 regulations at maximum speeds of .
History
In 1996, Amtrak placed an order for 15 HHP-8 locomotives alongside its acquisition of Acela Express trainsets, completing production between 1999 and 2001. Bearing a design aesthetic similar to the Acela power cars, these locomotives operated independently while hauling conventional passenger cars. They served as supplements to the EMD AEM-7 fleet and facilitated the phasing out of the GE E60. Rather than purchasing outright, Amtrak leased these units from Philip Morris Capital.
Initially labeled HHL-8 ("High Horsepower Locomotive, 8,000 nominal horsepower"), the designation was later changed to HHP-8. Simultaneously, MARC procured six HHP-8 units for use on its Penn Line, which runs along the Northeast Corridor between Perryville and Washington, DC.
Amtrak primarily deployed its HHP-8 locomotives on the Northeast Corridor route connecting Boston and Washington, DC; by 2009, each unit had logged approximately one million miles. In 2002, all fifteen Amtrak HHP-8s were temporarily removed from service alongside the Acela Express fleet following the discovery of cracks in bogie components.
Amtrak retirement
Due to the HHP-8 locomotives’ poor reliability, Amtrak decided to phase them out along with the aging AEM-7 units in order to reduce costs by standardizing its locomotive fleet. A replacement order comprising 70 locomotives was scheduled for delivery starting in 2012, with the HHP-8s maintained temporarily as backup units.
In October 2010, Amtrak placed an order for 70 Siemens ACS-64 locomotives to succeed both the HHP-8 and AEM-7 models, with deliveries commencing in early 2013. The final HHP-8 was withdrawn from service on February 9, 2015. All decommissioned locomotives were stored and renumbered from 680 to 694 to prevent numbering conflicts with the ACS-64 series. In 2019, Philip Morris initiated legal action against Amtrak, alleging lease breaches due to the dismantling of eight out of fifteen locomotives for spare parts. The dispute was resolved in 2021 under confidential terms.
Amtrak conversion to cab cars
To prolong the operational life of its equipment ahead of the introduction of Airo trains, Amtrak began experimenting with converting HHP-8 units into cab cars (designated HHP-8C) in 2023. This initial effort involved converting two locomotives to support expanded service on the Ethan Allen Express. Despite initial difficulties encountered with the first converted unit (originally numbered 691), the project was ultimately successful. By July 2024, Amtrak was evaluating expanding this conversion program to include up to eight units. In April 2025, units numbered 9750 and 9751 were revealed sporting Amtrak’s new Phase VII livery.
MARC refurbishment
Although there were reports in 2016 indicating MARC’s intention to retire its HHP-8 locomotives in favor of Siemens Charger units, MARC proceeded with a refurbishment initiative for its HHP-8 fleet in 2017. This effort primarily addressed cooling system problems that had negatively affected locomotive performance.
By September 2017, the first refurbished HHP-8 was delivered and underwent successful testing. As of March 2018, this locomotive had been in operation for three weeks requiring only minor software updates, while a second unit remained under refurbishment.
By June 2018, the second HHP-8 had undergone replacement of its most failure-prone power control components and returned to service, with additional improvements planned for completion by year-end. MARC intended to extend these upgrades across its entire HHP-8 roster.