“JetTrain”的意思、由来-开放百科全书

The JetTrain was an experimental high-speed passenger train created by Bombardier Transportation in an attempt to make European-style high-speed service more financially appealing to passenger railways in North America. It was designed to use the same LRC-derived tilting carriages as the Acela Express trains that Bombardier built for Amtrak in the 1990s and a similar locomotive. Unlike the Acela, powered electrically by overhead lines, the JetTrain locomotives used a combination of a diesel engine and multiple turboshaft engines. This would allow it to run at high speeds on non-electrified lines.

Description

Gas turbine engines

Turbine engines use as much as 65% of their overall generated power to run the compressor at the front of the engine. This means that when the engine is set to idle, with no net energy output, the engine is still burning 65% of the fuel it would at full speed.^[1] This makes turbine engines attractive only in roles where they are run at high power settings for long periods of time, as is the case in aircraft, power generation, or long-range train service. They are generally unattractive in roles where low-power operation is common, which is why they have also been unsuccessful in automobiles.

When jet fuel was very inexpensive in the 1950s and '60s the mechanical advantages of the engine -its inherent simplicity and very light weight- made up for the increased fuel costs. Several turbine-powered low-speed train designs were introduced during the 1950s and '60s, including both passenger and cargo engines. A number of high-speed passenger trainsets were also being designed in the 1960s, including the UAC TurboTrain in North America, the British Advanced Passenger Train (APT) and the French TGV 001.

By the 1970s, especially after the 1973 oil crisis, these advantages were no longer enough to overcome the increased fuel costs, and most turbine-based train designs disappeared. While two large classes of gas-turbine powered intercity railcars (ETG and RTG) continued to be used in France up until about 2000, both the TGV and APT switched to all-electric operation, with the installation of overhead lines to support them. In North America, where funding to upgrade rail lines was limited, electric operation was only an option for the busiest routes, and remains rare. Only Canadian National Railway (CN) and Via Rail continued to run their TurboTrains into the early 1980s, before they too were replaced with diesel-electric units, such as the LRC train.

JetTrain

Another change that has taken place over the last few decades is the widespread use and standardization of head end power (HEP) to provide electricity to the rest of the train for running the environmental controls and entertainment systems. Since these power requirements are fairly steady, even while the train is parked, it is not uncommon to use a separate engine just for this role, highly tuned to these operational needs.

The JetTrain expands on this idea by using the same HEP engine to provide motive power during low-speed operation, bypassing the problems with turbine fuel efficiency at low power settings. The JetTrain uses only this engine while it is moving about the station area and switchyards. Once the train has left the switchyard, the turbine engine, a {{convert|3750|kW|shp|0|abbr=on}} Pratt & Whitney Canada PW150 (called the ST40 in this role),^[2] is started and the train accelerates to operational speed. The diesel alone can run the train at speeds up to {{convert|50|km/h|mph|0|abbr=on}} when empty, and the turbine increases that to {{convert|240|km/h|mph|0|abbr=on}}. The two engines are geared together in a single gearbox which powers a generator to provide power to four traction motors, identical to those in the all-electric Acela Express. The generator is the motor from a TGV train, run in reverse of normal operation where instead of being hooked to electric power and producing rotation, it is rotated and produces electric power.

The major advantage to using the turbines for the high-speed portion is their light weight; the turbine weighs only {{convert|400|kg|lb|0|abbr=on}} while a conventional diesel of the same power would weigh as much as {{convert|10000|kg|lb|0|abbr=on}}. This lowers the weight of the power cars; the JetTrain power car is {{convert|215000|lb|t|1}} and had an unsprung weight per axle of {{convert|5530|lb|kg|0}}. This compares to the widely used EMD F40PH which weighs {{convert|260000|lb|t|1|abbr=on}} with an axle weight of {{convert|8540|lb|t|1|abbr=on}}. This reduction in mass per axle places considerably less stress on the rails, allowing the train to operate at higher speeds without changes to the railbed.^[3]

With a single power car towing seven passenger cars, the JetTrain could reach {{convert|170|km/h|mph|0|abbr=on}}, although its maximum "balance speed" was {{convert|220|km/h|mph|0|abbr=on}}. With two power cars, one at the front and one at the rear, the train reaches {{convert|240|km/h|mph|0|abbr=on}}, with a maximum speed of {{convert|265|km/h|mph|0|abbr=on}}.^[4] A complete train normally consists of two power cars, one at either end, along with up to 11 passenger cars. The passenger cars are versions of the ones used on the Acela, tracing their lineage to Bombardier's LRC tilting train introduced in the 1980s. In operation, the JetTrain is highly efficient. Due to its lighter weight and modern engine, the JetTrain has greenhouse gas emissions that are 30% lower than a diesel unit operating at the same speeds.^[5] The engine is practically silent even at full power: in operation the train is the same volume as the all-electric Acela.^[6]

History

The JetTrain originated in a 1997 Federal Railroad Administration (FRA) desire to develop high speed train services on routes outside the Northeast Corridor where route volumes might not be great enough to make electrification an option. The FRA went looking for an industrial partner who would be willing to invest on a 50/50 basis, and FRA spokesman Warren Flatau commented, "Bombardier is the company that stepped up to the plate when we put out the word we were interested in doing this project. We believe that the project holds great potential for bringing about the high speed services that people across the country are expressing a desire for." The final agreement was signed in October 1998, with the FRA and Bombardier each investing $13 million in the prototype, which was built at the new Bombardier Mass Transit Corporation plant in Plattsburgh, New York.

The prototype was completed in June 2000. Safety testing started at the FRA's Pueblo, Colorado, test track in the summer of 2001, where it reached a maximum speed of 156 mph. The prototype was then taken on a tour of potential high speed sites. Their primary target was the Florida Overland Express for passenger service between Orlando and Tampa in the United States. In support of this program, the prototype visited Miami on 7 October 2003 and Orlando on the 11th. The system was originally slated to open in 2009, but was denied funding by a referendum in 2004, after the start of detail engineering stages.^[7]

In Canada, Bombardier and Via Rail presented a proposal to use the JetTrain on Via’s busy Quebec City-Windsor Corridor as part of their ViaFast proposal, but were unable to obtain funding from the national government. In January 2008, the premiers of Ontario and Quebec announced a feasibility study for the Corridor, giving high speed trains another chance. The Van Horne Institute has also completed a study with Bombardier regarding the suitability of JetTrain service between the two largest cities in Alberta, Edmonton and Calgary.^[8] Other possibilities included new lines in Texas and to Las Vegas.

In the United Kingdom, the JetTrain has been proposed as a replacement for the 125 mph diesel-electric HST.^[9] Australian rail magazines have suggested the JetTrain as a viable option for high-speed rail in Australia to supplement the XPT (a version of the British HST) and Tilt Train.

Bombardier more recently has begun conversations with the state government of Yucatan in Mexico for the development of the Transpeninsular Fast Train. The project aims to connect the state capital of Mérida to the tourist resorts of the Mayan Riviera like Cancun and the Mayan Ruins of Chichen Itza. According to the Governor Ivonne Ortega, the train must run on diesel at an average speed of 100 mph, for which Bombardier deemed suitable the use of The JetTrain.^[10]

High Speed Rail Canada has assembled all the available known video footage of the Bombardier Jet Train and has posted them on their YouTube Page.^[11]

Description

Gas turbine engines

JetTrain

History

See also

References

Bibliography

Further reading

External links