603 kilometers per hour is until today the speed record for railway technology, established by the Japanese train model L0 (L zero), which operates through superconducting magnetic levitation (SCMaglev). This milestone summarizes a growing and global technological trend. The train, in speed, safety, efficiency and ecological impact, is gaining speed to reinvent itself in the 21st century as the most sustainable transportation alternative in times of climate emergency.
The new Japanese bullet train will link Tokyo and Nagoya in 2027 – if construction delays allow – in about 40 minutes, reaching maximum speeds of 500 kilometers per hour, to extend in 2037 to Osaka with a journey time of 67 minutes. Meanwhile, the prototype has already broken the world railway speed record, exceeding 600 kilometers per hour and maintaining that top speed for 11 seconds. And the key is precisely not to touch the rails. SCMaglev technology is based on electrodynamic suspension, a physical phenomenon that occurs by causing a repulsive magnetic field between two objects, which keeps them separated.
In the case of the bullet train this means that the car levitates 10 centimeters above the rails; That is, there is no friction between the train and the tracks that causes it to lose speed. To achieve this, the chassis has a series of superconducting magnets attached, powered by a gas generator, which create a magnetic field. The roads on which the vehicle circulates have coils installed that, when interacting with the magnetic field, generate their own field by induction. Due to their arrangement, these coils achieve a double effect: on the one hand, making the train levitate, and on the other hand, guiding and stabilizing its course. The levitation of the train occurs from 150 kilometers per hour and, until that moment, the train runs on rubber wheels.
In 2020, an improved version of the L0 series was presented that dispenses with gas turbines, since in this case the wagons are powered by induction from the electricity from the tracks. Therefore, the train does not consume any fuel or produce emissions, and the electricity to the tracks can be supplied from renewable sources, so the environmental impact is minimal. Although maglev trains consume a little more energy than conventional ones, their balance is very favorable even compared to the most efficient airplanes.
As far as conventional trains are concerned, currently just under a third of the global railway network is electrified, some 375,000 km out of a total of 1.3 million. This means that the vast majority of the network still relies on self-propelled locomotives, and diesel fuel has until now been the usual solution. Hybrid trains are today a transition step, but 100% electric trains are on the horizon.
In 2007 Japan introduced the first diesel-electric hybrid trains on a rural line. In 2015, the first intercity service began operating, traveling through the 20 stations that cover 47.2 kilometers of the Senseki-Tōhoku line at a maximum speed of 100 kilometers per hour. The advantage over a conventional train is that the emission of nitrogen oxides is reduced by 60% and diesel consumption by around 10%.
The hybrid engines in these trains are similar to those in cars. The ecological and efficiency improvement is provided by two 15 kilowatt-hour lithium batteries per car. The batteries change their behavior depending on the state of the train. When stopped, they power the train’s auxiliary systems. During start-up, and through an inductor that transforms the direct current of the batteries into alternating current, the train is started with the diesel engines turned off; Once the vehicle has started, the diesel engines begin to operate. The braking of the train is used to recharge the batteries.
However, despite the fact that this is a technology widely used in automobiles and easy to adapt to trains, this modality has not yet taken off and operates only on a minority basis or in pilot projects. The medium-term future bet would be the completely electric train, powered by batteries that avoid the need to lay catenaries or electrified rails. In reality, it is a very old idea: the first locomotive powered by electric batteries was manufactured in 1837, although the system did not spread. In recent times, Japan introduced battery-powered passenger trains in 2014, and the following year the United Kingdom tested an electric locomotive for commercial use for the first time in 50 years, a prototype of the IPEMU (Independently Powered Electrical Multiple Units) project that carried passengers. as part of a plan by the British national railway network to reduce its costs by 20%, in addition to curbing harmful emissions into the atmosphere.
The drawback of electric trains is the high weight of the batteries and their limited autonomy, which reduces their usefulness. For this reason, trains that combine batteries with a pantograph are often used to connect to a catenary, which allows them to travel partially electrified sections, so that the line recharges the batteries for non-electrified routes. Today there is interest in trimodal trains, which combine the batteries and pantograph with the diesel engine to offer greater versatility. Currently several countries make use of electric trains to a greater or lesser extent.
An alternative to electric trains is to generate their own energy from hydrogen, a renewable and non-polluting resource. This is the path proposed by hydrail technology. The two main strategies to achieve this are to either burn the hydrogen or use it in a fuel cell.
The fundamental difference is that in the first case the hydrogen is burned in an combustion engine (such as gasoline engines), without emitting CO2 but with nitrogen oxides, which contribute to the greenhouse effect that causes climate change. In the fuel cell, hydrogen reacts chemically with oxygen and in this case the only waste from the reaction is heat and water, which is why the vehicles that use this technology (FCEVs) are considered to be zero emission, that is That is, they do not pollute.
In the past decade, various hydrail technology projects began to come off the board and test. Aruba, a Caribbean island belonging to the Kingdom of the Netherlands, implemented the first regular hydrogen tram service in 2012, which was later followed by Dubai and other urban lines. However, the jump to large passenger trains has been slower. In 2016, the French company Alstom presented the Coradia iLint, the first passenger train powered by hydrogen cells, which began operating in Germany in 2018. Several European countries have already introduced iLints or plan to do so in the coming years, including Italy, France , Sweden, Poland, Austria, the Netherlands or the United Kingdom.
The monorail has been an option studied since the 19th century, and contemplated during the 20th century as the futuristic vision of the urban transportation system. However, it has been used primarily as a tourist attraction. Monorails for urban mass transportation today operate mainly in Japan and China. Lately there are several projects underway in cities such as Cairo, Bangkok or Bahia. The São Paulo monorail, planned to be the second longest and highest capacity in the world after that of Chongqing (China), transporting 500,000 passengers a day, is partially operational, but has suffered chronic delays that have delayed the completion of the project until 2024. 54 seven-car trains (INNOVIA 300 model from manufacturer Bombardier) will travel the 27 kilometers of metro line 15 in 50 minutes. They will do it in a completely automated way, without a human driver. Monorail passengers using the new end-to-end line will save one hour and ten minutes of travel time, compared to the time it would take to travel the same route by car (two hours).
At a time when sustainability has become a key objective, interest in the monorail has been revived. The savings of this transport system are also reflected in the railway infrastructure. The use of new materials (taken from aeronautics) allows for lighter systems, making the construction of the lines much cheaper, and they are 10% more energy efficient than a traditional metro.
The project of entrepreneur Elon Musk (co-founder of PayPal, Tesla and SpaceX) can hardly be called a train, who defined it as “a cross between Concorde, a railgun and air hockey” when he unveiled in 2013 his proposal for a new means of transportation, the hyperloop. But the scope of the idea is much better explained in figures: covering the 616 kilometers that separate San Francisco from Los Angeles in 30 minutes. That is, circulate at transonic speeds, those that are on the edge of supersonic (the sound barrier is broken at 1,234.8 kilometers per hour).
The technological miracle would be possible by treating the train as a projectile, which would circulate through a quasi-vacuum tube. At the front of the vehicle, a gigantic fan would absorb the air to prevent it from slowing down and causing turbulence. The quasi-vacuum tube would help achieve high speeds by offering one thousandth of the atmospheric pressure at sea level. And for propulsion, the same philosophy as the maglev: a repulsive electromagnetic field that would eliminate friction by levitating the vehicle.
The idea of hyperloop was born with the ambition to change the entire world economy. Cross the Pacific in one night to transport goods from the United States to China.
Distant cities simplified as points on an intercontinental metro line. However, over time expectations regarding this possible new means of transportation have moderated, due to doubts about its technical and economic feasibility and about its safety and comfort for passengers. There has been no progress on the proposed line between Los Angeles and San Francisco.
Musk conceived the project as “open source,” inviting other companies to join, and there are currently at least seven companies developing the system. One of them, Virgin Hyperloop, part of Richard Branson’s business group, carried out the first test with passengers in Las Vegas in November 2020, although reaching a modest speed of 172 km/h. The current hyperloop speed record was set in July 2019 by a small prototype from the Technical University of Munich, but its 463 km/h is still far below the 574.8 km/h achieved by the French TGV in 2007. , the fastest record of a conventional train.
The hyperloop today is the subject of various projects around the world, some of them already frustrated, such as that of Hyperloop Transportation Technologies, which sought to build the first line in the Californian Quay Valley. It is still too early to know if hyperloop will become a real thing or if it will end up being abandoned. Nor is the root of the project inspired by sustainability considerations; It has been argued that Musk’s idea of covering the tube with solar panels would not provide enough energy, so the energy aspects could also threaten the continuity of this dream of future transportation.
