HIGH-SPEED rail has come a long way since Japanese bullet trains started to run on the world’s first purpose-built high-speed railway, the 515km Tokyo - Osaka Tokaido Shinkansen, in 1964. There are now 18 countries in the world with purpose-built railways with a maximum speed of 250km/h and above. Apart from Morocco and Saudi Arabia, all the networks built so far are in Europe and Asia. High-speed lines are under construction in the United States, Indonesia, Thailand and India, with many more countries developing plans for new lines.
The most remarkable achievement has been in China which only opened its first 115km line linking Beijing with Tianjin in 2008. By the end of 2020, China’s high-speed rail network had reached 37,900km, including the world’s longest continuous high-speed line, the 3422km railway linking the port of Lianyungang with Urumqi. Many of the lines have a maximum operating speed of 350km/h. Spain, which has Europe’s largest high-speed network, is the only other country where 350km/h operation is permitted.
Rail transport is the only mode of commercial passenger transport where the maximum speed has steadily increased; air transport has returned to sub-sonic speeds since the demise of Concorde, which ended supersonic travel, and the speed of automobiles is limited due to safety concerns.
However, speed per se is never the only rationale for building high-speed lines. Indeed, the maximum speed should be a function of the commercial speed needed to achieve a competitive journey time, which will make the new railway viable in terms of traffic and revenue. A high-speed railway with gentle curves, no level crossings or conflicting train movements, and operated by trains with the same performance characteristics allows high average speeds to be maintained for long distances, which is the key to achieving short, highly-competitive journey times.
Although the standard-gauge Tokaido Shinkansen only had a maximum speed of 210km/h when it opened, subsequently increasing to 285km/h, it still represented a step change over the conventional line which was congested and constrained in terms of loading gauge and maximum speed due to the 1067mm track gauge.
Relieving congestion and the ability to separate slow passenger and freight trains from fast trains are often the reasons for building high-speed railways. Indeed, this is the rationale for building HS2, the London - Birmingham - Manchester/Leeds line in Britain. Other reasons for building high-speed lines are to reduce the distance by rail between major cities because the existing railway follows a circuitous route such as Madrid - Seville in Spain; to plug gaps in the network; or because the alignment of the existing network is very poor. The conventional network in Turkey for example suffers from all these deficiencies.
High-speed rail is now regarded as one of the tools in the fight against climate change by replacing short-haul flights and car journeys with high-speed trains. There is plenty of evidence of high-speed trains replacing jet aircraft as the dominant mode on key corridors such as London - Paris, Paris - Brussels, Madrid - Barcelona, Rome - Milan, and Tokyo - Osaka. Indeed, the European Union has set a challenge of doubling high-speed rail traffic by 2030 and tripling it by 2050. This will be achieved through a mixture of increasing traffic on existing lines and building new lines. Competition between operators could also have a role to play. The entry of NTV to compete with incumbent Trenitalia in Italy in 2012 increased the overall size of the market and raised quality standards. Hopefully, this will be replicated in Spain where competition is just starting.
The perception today among politicians and planners that rail has an important role to play in the transport mix is a far cry from the situation in the 1960s when rail was widely seen as an out-dated mode of transport with the future lying in cars and planes. The railway industry owes a debt of gratitude to Japan for helping to gradually change the perception of rail - the image of a bullet train speeding past Mount Fuji quickly became famous worldwide and synonymous with modernity.
“The Tokaido Shinkansen was called ‘Dream Super Express’ among Japanese people back then,” says Mr Naoyuki Ueno, general manager, Central Japan Railway (JR Central) in London. “I think it actually gave Japanese people hope, contributed to boosting the economy and dramatically cultivated the future of rail. The Tokaido Shinkansen had a great impact not only on Japanese people but also globally and gave an opportunity for the world’s railways to innovate.
“People all over the world understand that the Shinkansen is a pioneer of global high-speed rail and excels in its safety, punctuality, comfort and convenience, and they therefore trust the Shinkansen system. At the same time, we need to further enhance the Shinkansen system so that we can maintain the trust and expectation of people from around the world.”
Japan’s Railway Technical Research Institute (RTRI) says the opening of the Tokaido Shinkansen had not only a great socio-economic impact on Japanese society but also triggered a series of technical developments. These include bogies for high-speed trains with excellent running stability, distributed traction from the outset rather than trains formed of power cars and trailer coaches, and automatic train control systems (ATC) with cab signalling. “These developments laid the foundation for further improvement of the Shinkansen technologies in the following years,” RTRI says.
Japan’s high-speed network has steadily expanded since 1964 and now extends from Kagoshima in Kyushu to Shin Hakodate-Hokuto in Hokkaido, with several lines designed for 320km/h operation. Japan has transported about 6.6 billion high-speed rail passengers since 1964 and has suffered no fatalities due to a train accident, while the average train delay is less than one minute. “It is vital to constantly strive to achieve high levels of safety and punctuality,” Ueno says. “What we have to avoid is complacency in safety.”
Although Italy was the first country to open a high-speed railway in Europe - the first 138km section of the Rome - Florence Direttissima was inaugurated in 1977 - Italian State Railways (FS) lacked trains capable of operating at 250km/h. It was not until the first production ETR 450 tilting Pendolino entered service in 1988 that 250km/h operation started in Italy. The 254km line was not completed until 1992 due to technical and funding problems and Italy has since extended its first line north and south with 300km/h lines gradually forming a T-shaped network.
France started construction of its 409km Paris - Sud-Est line to Lyon in 1977 with the first section opening in 1981. As the Paris - Sud-Est line had a maximum speed of 260km/h and a fleet of TGVs capable of operating at this speed, France became the second country in the world to operate a high-speed railway and the first in Europe. This was followed by the completion of the first line in Germany between Hannover and Würzberg in 1991, and Spain’s first line between Madrid and Seville in 1992.
France achieved an important milestone in 1989 with the opening of the first stage of its Atlantique high-speed line as this was the first railway designed for 300km/h operation.
As the French high-speed network has steadily expanded, so has the technology.
“The real strength of TGV has been knowing how to constantly reinvent itself for 40 years, both technically and commercially.”Mr Antoine Leroy, traction manager with French National Railways (SNCF)
High-speed rail is a major driver of technical innovation as it requires the rail system to operate at peak performance in terms of ride quality, reliability and safety. The development of the Shinkansen, TGV in France and ICE in West Germany involved a huge effort by the railways, research institutes, universities, and manufacturers to develop the technologies needed for safe high-speed operation involving many years of experimentation and testing. Huge leap forwards were and continue to be achieved in areas such as track design and materials, electrification, aerodynamics, traction equipment, bogies, suspension systems, braking, train design, the all-important wheel-rail and pantograph-catenary interfaces, ride stability, train control, maintenance, and passenger comfort.
“The real strength of TGV has been knowing how to constantly reinvent itself for 40 years, both technically and commercially,” says Mr Antoine Leroy, traction manager with French National Railways (SNCF). “In 1981, the first TGV ran at 260km/h. Two years later, the commercial speed increased to 270km/h. In 1989, second generation TGV Atlantique trains came out of the factory with a maximum speed of 300km/h. Since 2007, new high-speed lines have seen TGVs operate at 320km/h.
“The real feat was to succeed in modifying the very first TGV trains built in 1980 and designed to run with a maximum speed of 270km/h by raising their maximum speed to 300km/h while guaranteeing a high level of reliability.
“In terms of signalling systems, techniques have evolved considerably. With the miniaturisation of components, we are able to pass more and more information between the track and the train despite very high speeds. The arrival of ERTMS in France and Europe is the culmination of all this progress.”
TGV Atlantique was the first high-speed train fleet to have on-board computing. “This revolutionised driving and maintenance,” Leroy says. “The driver was now able to interact with his machine via a computer and to know in real time the technical status of his train. These trains were also equipped with self-piloted synchronous motors compared with the first TGVs which were equipped with dc traction motors.
“In 1996, the arrival of TGV Duplex marked a major innovation in terms of technical performance. A new aluminium bodyshell structure enabled the train to respect the maximum axleload of 17 tonnes despite being a double-deck train. In 2006, the POS TGVs for operation on Paris - Frankfurt/ Munich services were fitted with asynchronous traction motors and ERTMS onboard equipment.”
France has a long tradition for setting world rail speed records. “Since March 1955 when the BB 9004 and CC 7107 locomotives recorded 331km/h, each record is an apprenticeship,” Leroy says. “A record attempt obviously makes it possible to test new technologies and above all to constantly learn how equipment on the roof or under the body will behave, and observe the evolution of train stability as a function of speed. Learning from the past allows us to take responsibility for our choices for future trains.
“For the 2007 record attempt with a TGV POS, the intermediate bogies were powered by permanent magnet synchronous motors. Even though the distributed traction solution was not retained on the following series (TGV 2N2 double-deck trains), the 2007 record taught us a lot about the gains that we could make in the fields of aerodynamics or pantograph contact with the catenary. It also showed us our limits. At 574.8km/h, the sensors on the nose of the TGV recorded pressures of around 7 tonnes per square centimetre. Beyond these speeds, the constraints borne by the equipment and the installations are more akin to aeronautics.”
A challenge for SNCF is to design equipment that is both energy efficient, while being able to meet the constraints of lines with steep gradients.
Apart from a project to extend the Sud Aquitaine line from Bordeaux to Toulouse, which is under study, Leroy says the future for high-speed rail in France is primarily the modernisation of existing facilities. The Paris - Sud-Est line will celebrate its 40th anniversary this year and is the busiest high-speed line in Europe with 240 trains per day. “Traffic went from 7 million passengers per year in 1981 to 44.5 million in 2017,” Leroy points out.
A major renovation of this line is currently underway at a cost of €607m. This covers the replacement of switches and crossings, the reinforcement of the catenary and power supply, and above all the installation of ERTMS. When the work is completed in 2025, it will be possible to increase the number of trains per hour and improve traffic regularity.
A challenge for SNCF is to design equipment that is both energy efficient, while being able to meet the constraints of lines with steep gradients, such as the Paris - Sud-Est line where gradients are of the order of 3.5%. “Aerodynamics is necessarily linked to these issues,” Leroy says. “The search for the best possible aerodynamics combined with optimised driving according to the profile of the line (gradient) will allow a considerable reduction in the energy consumption of a train.”
Several projects are currently under development in France to reduce energy consumption:
- the use of computers to enable drivers to optimise their driving - acceleration and braking - and save up to 10% of energy on a trip
- equipping TGVs with LED lighting in passenger areas to achieve 7% energy savings, and
- timed closing of the doors so as not to over-strain the air-conditioning and heating systems.
SNCF says it is happy to stick with its current maximum speed of 320km/h. “In the 2000s, there was a reflection within SNCF to increase the speed to 350km/h,” Leroy says. “But the various studies carried out have shown that the economic model is irrelevant given the additional costs, especially for equipment and infrastructure maintenance that this would have generated.”
While France may be sticking with 320km/h as a maximum speed, this is not the case elsewhere. China has several lines where trains can run at 350km/h. Distances between main cities in China are much longer than in Europe, so the higher speed can be justified. Britain’s HS2 aims to be the first railway with a maximum speed of 360km/h. While maglev technology (see panel below) offers the prospect of much higher speeds, there is still plenty of potential for developing steel wheel on steel rail high-speed technology.
New generation high-speed trains are being developed in Europe and Asia. JR Central introduced its next-generation N700S Shinkansen train last year. JR Central says the 285km/h 16-car train is the first in the world to use silicon carbide (SiC) devices in the traction system. SiC devices have a lower power loss, higher frequency and a higher current than Si devices.
The width of the converter system for N700S is half that of the conventional system used in series N700 trains, while the axial length of the six-pole traction motor for N700S is 10% shorter. The main transformer’s weight is reduced by applying a new cooling system rather than SiC applications. As a result, the N700S traction system weighs 20% less than the series N700 traction system.
The weight-to-power ratio of the six-pole motor for N700S is 20% less than on previous trains, which have conventional four-pole motors. The N700S also has a lithium-ion battery self-propulsion system allowing it to operate catenary-free at low speed in the event of an earthquake or power cut.
Testing has started with Alstom’s new Avelia Liberty trains which will replace Amtrak’s Acela trains on the Boston - New York - Washington DC Northeast Corridor. The 300km/h trains are fitted with a Tiltronix body tilting system to increase speed through curves. The trains are longer, power cars are shorter and overall passenger capacity is up to 30% higher than on the existing Acela trains. Alstom says the trains can be extended from nine cars up to 12 without any modification to the traction system, and the maximum speed can be increased to 350km/h without the tilting system.
Siemens is testing a coach for its Velaro Novo next-generation high-speed train. Velaro Novo will have a scalable traction system for maximum speeds ranging from 250 to 360km/h, with power outputs ranging from 4.7MW to 8MW for a 202m-long seven-car train.
Aerodynamic improvements include a streamlined bogie housing, gangway connections, pantograph shrouding and covered high-voltage equipment on the roof.
Siemens says the train will be around 15% lighter than the current Velaro, reducing the weight of a seven-car train by more than 70 tonnes. This has been achieved through the use of inside-frame bogies, silicon carbide auxiliary converters, and the use of friction-stir welding for bodyshell fabrication. Both Avelia and Velaro Novo use the hollow tube concept for coach design to maximise the flexibility of the design of the train interior.
Finally, China opened the 174km Beijing North - Zhangjiakou line on December 30 2019, the world’s first automated high-speed railway. The line is equipped with Automatic Train Operation (ATO) over China Train Control System (CTCS) Level 3. China National Railway says the use of ATO on the line will increase capacity by enabling trains to operate at shorter headways and with greater reliability while reducing energy consumption.
France and Germany are also pursuing automatic operation, which could be the next major leap forward in high-speed rail technology.
Maglev: more pragmatic than Hyperloop
MAGLEV technology is only being pursued for high-speed inter-city travel in Asia following the abandonment of Germany’s Transrapid maglev system when the Emsland track closed in 2011, despite a 30.5km line being built to connect Shanghai Pudong International Airport - with Longyang Road metro station in the southeast of Shanghai.
JR Central is constructing the first phase of the Chuo Shinkansen 500km/h superconducting maglev line to initially connect Tokyo with Nagoya and eventually Osaka.
“Currently, terminal stations at Shinagawa in Tokyo and Nagoya are under construction, as well as mountain tunnels and emergency exits,” says Mr Naoyuki Ueno, general manager, Central Japan Railway (JR Central) in London. “We have proceeded with designing, surveying, and land-acquisitions, cooperating closely with local areas.
“However, it will be difficult to start operation in 2027 as originally planned, because construction work in Shizuoka has stalled. This is due to Shizuoka prefecture and other local governments having concerns about water supplies to the local areas. We are committed to solving this issue as soon as possible and will begin construction with the aim of opening the first phase section once concerns have been resolved.”
“Currently, terminal stations at Shinagawa in Tokyo and Nagoya are under construction, as well as mountain tunnels and emergency exits.”Mr Naoyuki Ueno, general manager, Central Japan Railway (JR Central)
Ueno says the Chuo Shinkansen will provide a second transport artery linking Tokyo, Nagoya, and Osaka. “It will help us prepare for risks posed by an ageing Tokaido Shinkansen line as well as large-scale natural disasters. We expect journeys between Tokyo, Nagoya, and Osaka will be shifted to the new Chuo Shinkansen line. Therefore, we may be able to pursue new opportunities such as increasing the number of Hikari and Kodama express trains on the Tokaido Shinkansen line, which have more stops and could further improve travel convenience for local residents.”
Two maglev train projects are underway in China. CRRC Sifang completed low-speed dynamic testing of a 600km/h prototype maglev car on a test track at Tongji University in Shanghai in 2020, a milestone for the project launched in June 2016. A full prototype train capable of 600km/h operation was expected to be completed by the end of last year. China announced plans in 2019 for a 200km maglev line in Hubei province to test operation of the prototype train at speeds in excess of 600km/h.
A prototype maglev car with a design speed of 620km/h was unveiled in Chengdu on January 13, along with a 165m-long test track. The 21m-long,
12-tonne power car, which uses high-temperature superconducting (HTS) maglev technology and has a carbon fibre lightweight body, was developed by Southwest Jiaotong University, China National Railway and CRRC. High-temperature superconducting maglev technology is a cheaper alternative to low-temperature superconducting technology which is used in earlier projects.
Professor Sun Zhang, a railway expert at Shanghai Tongji University, says the new train is designed for operation at normal atmospheric pressure, rather than in a vacuum tube as with Elon Musk’s Hyperloop where much higher speeds are proposed. “The Chinese trains are pragmatic while Musk’s Hyperloop is futuristic,” Sun told China’s Global Times.