Acela Express

The ***Acela Express*** (/əˈsɛlə/ *ə-SEL-ə*; colloquially abbreviated to ***Acela***) is Amtrak's flagship service along the Northeast Corridor (NEC) in the Northeastern United States between Washington, D.C. and Boston via 14 intermediate stops, including Baltimore, Philadelphia, and New York City. The route contains segments of high-speed rail, and *Acela Express* trains are the fastest trainsets in the Americas; they attain 150 mph (240 km/h) on 33.9 mi (54.6 km) of the route.[7]

*Acela* carried more than 3.4 million passengers in fiscal year 2016; second only to the slower and less expensive *Northeast Regional*, which had over 8 million passengers in FY 2016. Its 2016 revenue of US$585 million was 25% of Amtrak's total.[1]

*Acela* operates along routes that are used by freight and slower regional passenger traffic, and reaches the maximum allowed speed of the tracks only along some sections, with the fastest peak speed along segments between Mansfield, Massachusetts and Richmond, Rhode Island. *Acela* trains use tilting technology, which helps control lateral centrifugal force, allowing the train to travel at higher speeds on the sharply curved NEC without disturbing passengers.[8] The high-speed operation occurs mostly along the 226 mi (364 km) route from Pennsylvania Station in New York City to Union Station in Washington, D.C., with a fastest scheduled time of 2 hours and 45 minutes and an average speed of 82.2 mph (132.3 km/h), including time spent at intermediate stops.[3][9] Over this route, *Acela* and the *Northeast Regional* service captured a 75% share of air/train commuters between New York and Washington in 2011, up from 37% in 2000.[10]

The *Acela'*s speed is limited by traffic and infrastructure on the route's northern half. On the 231 mi (372 km) section from Boston's South Station to New York's Penn Station, the fastest scheduled time is 3 hours and 30 minutes, or an average speed of 66 mph (106 km/h).[2][11] Along this section, *Acela* has still captured a 54% share of the combined train and air market.[12][13] The entire 457 mi (735 km) route from Boston to Washington takes between 6 hours, 38 minutes and 6 hours, 50 minutes,[2] at an average of around 70.3 mph (113.1 km/h).[14]

The present *Acela Express* equipment will be replaced by new Avelia Liberty trainsets, beginning in 2021. The new trains will have greater passenger capacity and an active tilt system that will allow faster speed on the many curved sections of the route. Amtrak plans to retire all current Acela trains by the end of 2022.[15]

## History

### Background

Following the success of Japan's newly inaugurated Shinkansen network, the High Speed Ground Transportation Act of 1965 authorized the U.S. government to explore the creation of high-speed rail, which resulted in the introduction of *Metroliner* trains, the predecessor to *Acela*. During the 1980s the U.S. Federal Railroad Administration explored the possibilities of high-speed rail in the United States. On December 18, 1991, five potential high speed rail corridors were authorized ("Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) (PL 102-240)") including the Northeast Corridor.[16]

Amtrak asked railway equipment manufacturers to submit proposals. An X 2000 train was leased from Sweden for test runs from October 1992 to January 1993. It was operated from Washington, D.C. to New York City from February to May and August to September 1993. Siemens showed the ICE 1 train from Germany, organizing the ICE Train North America Tour which started to operate on the Northeast Corridor on July 3, 1993.[17] This testing allowed Amtrak to define a set of specifications that went into a public tender in October 1994.

On March 9, 1999, Amtrak unveiled its plan for a high-speed train, the *Acela Express*.[19] Twenty new trains were to run on the Northeast Corridor.[20] Several changes were made to the corridor to make it suitable for the *Acela*. The Northend Electrification Project extended existing electrification from New Haven to Boston to complete the overhead power supply along the 454-mile (731 km) route, and several grade crossings were improved or removed.[20][21][22]

In October 1994, Amtrak requested bids from train manufacturers for a trainset that could reach 150 miles per hour (240 km/h).[18] A joint project of Bombardier (75%) and GEC Alsthom (now Alstom) (25%) was selected in March 1996.[18] An inaugural VIP run of the *Acela* occurred on November 16, 2000,[23] with the VIP train being led by power car number 2020 with no. 2009 at the opposite end, followed by the first revenue run on December 11, 2000, a few months after the intended date.[24]

By 2005, Amtrak's share of the common-carrier market between New York and Boston had reached 40%, from 18% pre-*Acela*.[25] With the increasing popularity of the faster, modern *Acela Express*, *Metroliner* service was phased out in late 2006.[26][27] To meet the demand, more *Acela* services were added in September 2005.[28] By August 2008 crowding had become noticeable.[29]

By 2011, the *Acela* fleet had reached half of its designed service life. Amtrak proposed several replacement options, including one as part of its *A Vision for High-Speed Rail in the Northeast Corridor*.[5] In 2011, Amtrak announced that forty new *Acela* coaches would be ordered in 2012 to increase capacity on existing trainsets. The existing trains would have received two more coaches, lengthening the trainsets from a 1-6-1 configuration to 1-8-1 (power car — passenger cars — power car). The longer trainsets would have required the modifications of the *Acela* maintenance facilities in Boston, New York and Washington. The first of the stretched trainsets was to have entered service in fiscal year 2014.[30] This plan was cancelled in 2012 in favor of replacing, rather than refurbishing, the *Acela* fleet.[31]

In January 2014, Amtrak issued a request for proposals on 28 or more new model *Acela* trainsets, in a combined order with the California High-Speed Rail Authority. These bids were due May 17, 2014.[32] After discussions with manufacturers, Amtrak and the California High Speed Rail Authority concluded their needs were too disparate for common rolling stock and decided not to pursue the joint option.[33]

### Cost

Amtrak's original contract with the Bombardier-Alstom consortium was for the delivery of 20 trainsets (6 coaches each, with power cars at front and rear) for $800 million.[34] By 2004, Amtrak had settled contract disputes with the consortium, paying a total of $1.2 billion for the 20 trainsets plus 15 extra high-speed locomotives and the construction of maintenance facilities in Boston, New York, and Washington.[35]

## Engineering

The first-generation *Acela* trainset is a unique set of vehicles designed specifically to satisfy governmental rolling stock requirements established primarily by the Federal Railroad Administration (FRA). This includes the ability to withstand a collision with a freight train at speed without collapsing. Most manufacturers which bid on the *Acela* were unable to meet the structural requirements, due to increased costs and complications for the manufacture of the trains, and the need for manufacturers to make significant engineering changes to their standard designs. In the end, only three qualified bidders remained: ABB (Swedish-Swiss manufacturer of the X 2000 train), Siemens (manufacturer of the German ICE), and a consortium of Bombardier (manufacturer of the LRC trains) and Alstom (manufacturer of the French TGV).[25]

The design, using identical 6,200 horsepower (4,600 kW) power cars at each end which operate on a voltage of 11,000 volts AC, and either 25 or 60 Hz frequency, derives several components from the TGV,[46] such as the third-generation TGV's traction system (including the four asynchronous AC motors per power car, rectifiers, inverters, and regenerative braking), the trucks/bogies structure (a long wheelbase dual transom H frame welded steel with outboard mounted tapered roller bearings), the brake discs (although there are only three per axle, versus four on the TGV), and crash energy management techniques to control structural deformation in the event of an accident.[45][46]

The tilting carriages are based upon Bombardier's earlier LRC trains used on Via Rail rather than the TGV's non-tilting articulated trailers. *Acela* power cars and passenger cars are much heavier than those of the TGV in order to meet the FRA's crash standards.[47] French and Canadian crews testing the *Acela* referred to it as "the pig" due to its weight.[48][49] The extra weight leads to the *Acela'*s power-to-weight ratio being about 22.4 hp per tonne, compared to 30.8 hp for a SNCF TGV Reseau trainset.[46] The Tier II crash standards, adopted in 1999, have also resulted in the passenger cars being designed without steps and trapdoors, which means that the trainsets can only serve lines with high-level platforms such as the Northeast Corridor. *Acela* trains are semi-permanently coupled (but not articulated as in the TGV) and are referred to as trainsets. Bombardier later used the *Acela* carriage design and a diesel/gas turbine variant of the power car for its experimental JetTrain.[50]

### Operating speeds

With a 71:23 gear ratio, the *Acela* is designed with a top speed of 165 mph (266 km/h) and reaches a maximum speed of 150 mph (240 km/h) in regular service on three sections of track totaling 33.9 miles (55 km) in Rhode Island and Massachusetts.[7] The *Acela* achieves an average speed (including stops) of 82.2 mph (132.3 km/h) between Washington and New York,[3][9] and an average speed of 66 mph (106 km/h) from New York to Boston.[2][11] The average speed over the entire route is a slightly faster 70.3 mph (113 km/h).[2][14]

In practice, the *Acela'*s speed depends more on local restrictions along its corridor than on its trainset. In addition to speed restrictions through urban areas, the *Acela**s corridor includes several speed restrictions below 60–80 mph (97–129 km/h) over older bridges, or through tunnels a century old or more. Altogether, Amtrak has identified 224 bridges along*****Acela**s route that are beyond their design life.[51]

To prepare for the *Acela* launch, Amtrak upgraded the track along the Connecticut shoreline east of New Haven to allow maximum speeds in excess of 110 mph (177 km/h).[52] West of New York City, the *Acela'*s top speed is 135 mph (217 km/h).[7] One limiting factor is the overhead catenary support system which was constructed before 1935 and lacks the constant-tension features of the new catenary east of New Haven.[5] The Pennsylvania Railroad ran *Metroliner* test trains in the late 1960s as fast as 164 mph (264 km/h) and briefly intended to run the *Metroliner* service at speeds reaching 150 mph (241 km/h). Certification testing for commercial operation at 160 mph (257 km/h) involving test runs at up to 165 mph (266 km/h) began between Trenton and New Brunswick in September 2012.[53]

The slowest section of the electrified NEC is the portion owned by Metro-North Railroad and the Connecticut Department of Transportation between New Haven, Connecticut and New Rochelle, New York and is heavily used by commuter trains. Amtrak's trains here achieve 90 mph (145 km/h) only on a limited 4 mi (6.4 km) stretch in New York State and rarely exceed 60 mph (97 km/h) at any time eastbound through Connecticut until reaching New Haven.[54] In 1992, ConnDOT began plans to upgrade the catenary system, replace outdated bridges, and straighten certain sections of the New Haven Line to enable the *Acela* to run slightly faster. Curve straightening was later deemed too expensive.[*citation needed*] As of May 2017 the catenary replacement and bridge work were under way and expected to be completed by mid-2018.[55]

On July 9, 2007, Amtrak introduced a limited-stop round trip, with trains stopping only at Philadelphia between New York and Washington. This shortened the trip between the two cities to 2 hours 35 minutes, making the trip roughly an hour faster than some of the *Northeast Regional* train services. These trains were an experiment to find ways to expedite travel time on the *Acela*; Amtrak has since dropped them.[56]

*Acela Express'*s fastest schedule between New York and Washington, DC was 2 hours and 45 minutes in 2012. $450 million was allotted by President Barack Obama's administration to replace catenary and upgrade signals[57] between Trenton and New Brunswick, which will allow speeds of 160 mph (257 km/h) over a 23 mi (37 km) stretch. The improvements were scheduled to be completed in 2016, but have been delayed; the project is now scheduled to be finished in 2020.[58] This section of track holds the record for the highest speed by a train in the US, which is 170.8 mph (274.9 km/h), achieved in a test run by the U.S./Canada-built UAC TurboTrain on December 20, 1967.[5][59]

### High speed infrastructure

The dense population of the northeastern United States makes the Northeast Corridor the most heavily traveled portion of the American passenger rail system. Two-thirds of rail passengers in the United States live in or near New York City, also home to the nation's busiest passenger rail station, Penn Station.[60] In order to compete with airliners, Amtrak needed to increase the speed of trains in the region. The former Shore Line from New Haven to Boston is burdened by sharp turns and grade crossings, the crossings being of special concern.[61]

Tilting enables passengers to ride more comfortably on curved sections of track faster than would otherwise be possible, by leaning into the bend. *Acela* trainsets tilt above 60 mph (97 km/h) on most of the system, but some segments of track in the Northeast Corridor are too close together for the cars to safely tilt while maintaining FRA minimum space between trains on parallel tracks. Metro-North Railroad restricts tilting on the segment of track north of New York which it owns. The system was originally designed for a 6.8° tilt, but the cars were redesigned 4 in (100 mm) wider to accommodate wider seats and aisles that reduced allowable tilt to 4.2° to fit within the clearance constraints of the existing tracks.[45] Traveling at higher than 135 mph (217 km/h) also requires constant-tension catenary, which is only implemented on the more modern catenary system north of New York City. South of New York City, the trains are restricted to 135 mph (217 km/h). By comparison, the *Northeast Regional* and the now-defunct *Metroliner* service reached 125 mph (201 km/h).

*Acela* service was originally expected to begin in late 1999 but was delayed. The catenary system could not support the intended speeds between Washington DC and New York City, but the newer system between New York City and Boston allows the higher speeds. Attention was drawn to the decreased 4.2° tilt, but this was not the root of the speed problem, as the tracks from New York to Boston are similar to those between New York and Washington, and the tilt mechanism is not the factor enabling higher speeds.[18][45] Following repairs, the first *Acela* service began on December 11, 2000, a year behind schedule.[62]

*Acela* travels between Boston and New York in about three and a half hours (an improvement of half an hour); New York to Washington runs take a minimum two hours and forty-five minutes.[2] These schedules, as well as the relative convenience of direct downtown-to-downtown rail service as opposed to air travel, especially after the September 11 attacks, have made the *Acela Express* more competitive with the air shuttles. Due to this competition, Southwest Airlines canceled service between Washington and New York.[63]

#### Platform track speeds

Due to the high speed at which *Acela* trains bypass platforms of local stations, concerns have mounted in some communities over inadequate warnings and safeguards for passengers waiting for other trains, including that the two-foot wide yellow platform markings may not keep people at a safe distance. At Kingston station in Rhode Island and Mansfield station in Massachusetts, *Acela* trains pass by at 150 mph (241 km/h).[64][65] Suggestions include platform safety barriers, or use of different announcements for approaching *Acela* trains versus slower ones.[66] In 2011, federal transportation grants were awarded to improve Kingston station, including the construction of a third track to be used by the *Acela* as a through track to bypass the station, helping to alleviate safety concerns.[67] Renovations were officially completed on October 30, 2017.[68][69]