2021 has been chosen as the European year of railways. The train, born in 1825 with the invention of the steam locomotive, after almost two centuries of history returns to be a symbol of progress and technical innovation, but in an inverted perspective: if in the art and literature of the nineteenth century the train it is a symbol of an aggressive modernity, which aims at profit by crushing the weakest and disturbing the harmony of the rural world, today it seems a valid solution to combat pollution and achieve the objectives of the European Green Deal. Indeed, rail transport is among the most energy efficient systems with the lowest levels of emissions: in 2017 it was responsible for just 0.4% of transport-related emissions, compared to 72% for road transport . In addition, transport on electrified rail can benefit from an electricity mix that increasingly uses renewable sources at national level. Furthermore, it appears to be a safe transport system, second only to aircraft for the lowest accident rate: 0.1 accidents per billion passengers per kilometer between 2011 and 2015. But what are the technical and energy challenges for the future in this sector? Today 40% of the main European railway lines run trains powered by diesel engines, but things are changing. In Italy, the obsolescence of diesel-powered cars could accelerate the transition to greener cars.
The first step in this transformation process will be the hybrid trains, powered by a "PowerPack", a module consisting of two latest generation low-emission diesel engines and between two and four batteries. This solution is becoming increasingly popular thanks to rapid technological advances on batteries, which have ever greater autonomy. During circulation, these trains can switch from the power supply to the internal combustion engine, reducing consumption. Hybrid trains are increasingly equipped with a system for recovering and reusing braking energy, used to power the train itself and other auxiliary equipment. Compatible with both electric and diesel power, energy recovery occurs simply by reversing the operation of the electric powertrain: when you lift the pedal or brake slightly, instead of converting the current into motion, the engine "transforms" into an alternator and converts the kinetic energy back into electric current. The aim is to cut GHG emissions and reduce maintenance costs related to fuel, electricity and engine maintenance. Another advantage of hybrid trains lies in the possibility of using batteries in the vicinity of inhabited places, considerably reducing the noise of trains and emissions. Trenitalia adapts: in 2020 it orders the Japanese Hitachi to build hybrid regional trains, which will come into circulation starting this year in Sicily, Sardinia, Tuscany, Val d’Aosta and Lazio. The ultimate goal is a zero-emission train: fully electric or hydrogen-powered.
According to a study by Roland Berger, trains powered by hydrogen systems could gain 20% market share in Europe by 2030 . Hydrogen seems to be the solution to decarbonate railway systems without sacrificing the current performance of trains. The heart of these convoys is the fuel cell, where the oxygen taken from the environment is combined with the hydrogen stored in special tanks, producing electricity. The only drain is made up of condensation water and water vapor; also in this case the noise is minimal. Research in this field will allow to accumulate knowledge on hydrogen, a crucial element for the energy transition, and to promote the diffusion of infrastructures for the use of hydrogen as a fuel, with consequent reduction of costs for other mobility alternatives that want to exploit this resource: think of common refueling stations between trains, buses and cars that will be powered with the same technology. For the moment, the main technological challenges are the production of hydrogen from renewable sources and its storage. A pioneer in the sector is the French Alstom, which has put two hydrogen trains into service in Germany since 2018.
Alstom is also working on the production of battery electric regional trains, which should enter service in 2023 in Germany. These trains, powered by high-power lithium batteries and able to run on both catenary and non-electrified lines, will be able to reach speeds of up to 160 km / h, with a range of 120 kilometers, without giving up. to the comfort and performance of its diesel-powered cousins. But innovation is not measured only on train power systems: the entire railway infrastructure is undergoing major transformations. Think of the startup GreenRail, born in 2012, which produces sleepers for rails, generally made of wood, with recyclable materials, mainly tires and plastic. In this way, not only are these materials recovered and reused (for a kilometer of road, about 35 tons of end-of-life tires and plastic from urban waste), but there is also a reduction in maintenance costs, as these materials are much more resistant than wood. A further innovation is constituted by the "Solar" sleepers, or sleepers with small solar panels, which transform the railway lines into photovoltaic fields. Finally, digital is also proposed in this sector as a driver of change. The digital transformation looks at different aspects of the railway world: network design, development of maintenance and renewal strategies, planning and optimization of routes. They range from sensors that predict technical malfunctions with vibration monitoring and temperature control, to driverless trains, up to apps for online ticket sales or for choosing a route, displayboards updated in real time on train times and position. All solutions that will contribute to improving services and reducing costs and waste. The new trains will be connected with an intelligent infrastructure: they will be able to know the position of other trains on the line, eliminating the need for traffic lights, and adjusting speed based on traffic, for more efficient fuel management. It will be possible for drivers to be updated on delays and weather events; it will be possible to analyze the flow of passengers in the stations in real time through the use of cameras, in order to concentrate more trains in case of high turnout, for example after matches or concerts.
In this rapid transformation process, care must be taken to invest in the right way: introducing new technologies into old processes does not automatically bring value. Only coherent long-term planning focused on the interconnection between all individual projects can pave the way for a real green revolution in the railway sector.
Translated by Arianna Giannino
 2021: the European Year of Rail, 12-01-2021, News - European Parliament, https://www.europarl.europa.eu/news/en/headlines/eu-affairs/20210107STO95106/2021-the-european-year-of-rail
 Fuel cell and hydrogen trains: an ultra greenrevolution for Europe’s Railroads, 17/05/2019 , Roland Berger, https://www.rolandberger.com/en/Insights/Publications/Fuel-cell-and-hydrogen-trains-An-ultra-green-revolution-for-Europe's-railroads.html