Acela Express (trainset)

History

In the early 1990s, Amtrak borrowed European high-speed trains to see if they could work on the Northeast Corridor. A Swedish X 2000 set ran tests from October 1992 to January 1993, then carried paying passengers between Washington, D.C., and New York City from February to May and again from August to September 1993. Siemens brought over a German ICE 1 train for a North American tour, and it started running on the corridor on July 3, 1993. Based on these trials, Amtrak drew up requirements and put out a public call for bids in October 1994.

The winning design had to hit 150 mph and survive a high-speed crash with a freight train without collapsing. Most companies that bid found these structural demands too tough, because they drove up costs and forced major changes to their existing designs. Only three bidders made the cut: ABB, which built the X 2000; Siemens, which built the ICE; and a partnership between Bombardier (maker of the LRC trains) and GEC Alsthom (maker of the French TGV).

In March 1996, Amtrak chose that consortium, with Bombardier holding a 75% stake and GEC Alsthom (now Alstom) the other 25%. A test trainset was finished by early 2000 and sent to the Transportation Technology Center in June 2000. A special VIP run took place on November 16, 2000, with power car number 2020 leading and number 2009 on the rear. The first revenue service started on December 11, 2000, a few months later than planned.

Outages

Amtrak’s original deal called for 20 trainsets, each with six coaches and a power car at each end, for $800 million. By 2004, after settling contract disputes, Amtrak paid $1.2 billion for those 20 sets, plus 15 extra electric locomotives and the construction of maintenance shops in Boston, New York, and Washington. In August 2002, not long after the trains entered service, they were pulled from operation because the brackets connecting the yaw dampers (shock absorbers) on the power cars’ trucks to the carbodies were cracking.

The trains went back into service after Amtrak set up a schedule of frequent inspections. The damper brackets were later redesigned, and all the old ones were swapped out for the new version.

Engineering

Each Acela trainset is built with a 6,200 horsepower power car at both ends, and these power cars can operate on three different AC electrical systems: 25 kV 60 Hz from Boston to New Haven, 12.5 kV 60 Hz from New Haven to New York City, and 12 kV 25 Hz from New York City to Washington, D.C. The trainset borrows many parts from the TGV, including the third-generation TGV's traction system—which uses four asynchronous AC motors per power car, along with rectifiers, inverters, and regenerative braking—as well as the bogie structure (a long-wheelbase, dual-transom H-frame made of welded steel with outboard tapered roller bearings), brake discs (though each axle has three instead of four), and crash energy management techniques designed to control structural deformation during a collision.

However, the tilting passenger cars are based on Bombardier's earlier LRC trains used by Via Rail, not on the TGV's non-tilting articulated trailers. To meet the Federal Railroad Administration's crash standards, the Acela's power cars and passenger cars are significantly heavier than those of the TGV. French and Canadian test crews nicknamed the Acela "the pig" because of this weight. The extra mass gives the Acela a power-to-weight ratio of about 22.4 horsepower per tonne, compared to 30.8 for a SNCF TGV Reseau set.

Because of the Tier II crash standards adopted in 1999, the passenger cars lack steps and trapdoors, limiting the trains to routes with high-level platforms, such as the Northeast Corridor. The cars are semi-permanently coupled but not articulated like the TGV, and each group is called a set.