Measurement and Analysis of Acela Express Regenerative Power Recovery

Amtrak launched the first high-speed Acela Express passenger train service in the USA in 2000 on the Northeast Corridor (NEC) between Washington, D.C, New York, and Boston. The NEC infrastructure is used by several other railroad/transit agencies that operate commuter train services under operating access agreements with Amtrak. With such an arrangement, all NEC passenger railroad/transit agencies contribute to the electrical demands of the traction power system on the southern division and in particular, between New York, and Washington, D.C. Amtrak and the other railroad/transit agencies conduct periodic reviews of the cost-sharing arrangements for the electricity bills. As part of a recent review, accurate data on the power usage by the Acela Express fleet was needed. The Acela Express power cars are equipped with modern traction drives with controls that are capable of recovering some or all of the regenerative braking power they produce. The use of regenerative braking is automatically controlled by the onboard Braking Control Computer via the internal propulsion and braking network. This feature makes the Acela Express trains efficient in energy consumption and affects the cost allocation to Amtrak. The extent of the energy recovery is dependent on how receptive the traction power system is when power is being regenerated from braking. In order to obtain realistic data, two separate Acela Express power cars were instrumented. A large amount of data was collected in normal service conditions from the onboard instrumentation. This paper describes the instrumentation and the data collection procedure, and presents the analysis results of the collected data. The analyses were focused on two parameters: the “energy recovery ratio” and the “system receptivity” of the traction power supply system. The study contributed to the successful conclusion of a new electrical cost-sharing arrangement among the NEC passenger railroad/transit agencies, which was made public in October 2006.