The complete electrification of rail networks offers several advantages, especially regarding the reduction of emissions. Electric railways rely significantly less on non-renewable fossil fuels and generate fewer emissions over time. Electric railways also improve efficiency and decrease levels of noise pollution in the areas directly around the train tracks. When trains are connected to the electricity network, they can also take advantage of power regeneration through braking, improving efficiency and reducing the energy required.
A study from the European Commission estimates rehabilitation and electrification on conventional rail may cost between 0.4 and 0.6 M EUR/km, with high variability due to environment, line type, and service type.
The state of rail electrification is relatively advanced, and estimates have found that globally, 75% of passenger rail uses electricity, with diesel making up the remaining 25%. Over 60% of the European rail network is already electrified, and 80% of total rail traffic runs on electric lines. According to data from Statista, Switzerland is the only European country that has electrified its entire railway network. Other countries like Luxembourg, Montenegro, and Belgium have electrified 80-90% of their network.
China is undergoing a rapid electrification push. In 2018, the combined length of electrified railways and double-track rail was 86600 and 71800 kilometres, respectively, accounting for 68% and 57% of the country’s total railway mileage.
Hydrogen competes with electrified and conventional diesel trains as an alternative to decarbonise trains on hard-to-electrify lines. However, hydrogen cannot meet the energy demands of high-speed and freight trains due to the lower relative energy density of energy and speeds required on conventional rail networks. For these trains, electrification is the only available technology.
The shift to hydrogen tends to be a preferred solution for old diesel trains on the non-electric tracks and maybe more cost- and time-effective than building overhead lines to electrify the network. Train producers can build these hydrogen fuel cell trains with large hydrogen tanks, so it is possible to only charge them at specific charging points, suitable for more rural routes.
Between September 2018 and May 2020, Alstom, the French transport manufacturing company, conducted a 530-day trial of its Coradia iLint hydrogen-powered train on the German Weser-Elbe network. From 2022, 14 Coradia iLint trains began replacing the existing diesel stock in Lower Saxony. Orders for the train have now been made in France, Italy and further tests have been conducted in Austria, the Netherlands and Germany. Alstom and British rolling stock company Eversholt Rail have also led a UK pilot project to consider the feasibility of converting existing Class 321 trains to hydrogen, referred to as the “Breeze” train.
HydroFLEX is a UK-based hydrogen train scheme run by Birmingham Centre for Railway Research and Education and railway rolling stock company, Porterbrook. One of its goals is to retrofit existing trains with the necessary equipment to run on hydrogen. Its first successful trial test took place in September 2020, when a HydroFLEX train made a return trip from Quinton Rail Technology Centre to Evesham. HydroFLEX is now working on securing its technology to the underside of carriages to increase space for passengers.
Scottish Enterprise and Transport Scotland are supporting the Zero Emission Train Project to develop the use of hydrogen trains in the Scottish rail network. It operated a hydrogen train on a closed rail network for a showcase at COP26.
The Swiss rail manufacturer Stadler has secured a contract from the San Bernardino County Transportation Authority in California to deliver the first hydrogen-powered trains in the US.
Aside from the fuel used to power the trains, increasing their energy consumption can reduce direct or indirect emissions. In most cases electricity costs are billed on the basis train weight, mileage and average consumption, which discourages energy savings for the respective train operator. As with every mode of transport, reducing emissions and increasing efficiency is of the utmost importance. Several strategies for increasing efficiency in trains and rail systems includes:
- Optimisation of timetables to maintain balanced network loads
- Timetable-based preparation time – the heating systems are switched on only in trains that will actually be utilised ahead of time. This has resulted in reduced energy consumption by 4 GWh per year in Switzerland, where such a system has been trialed.
- Application of more efficient cooling, e.g. dry-type transformers
- Utilisation of RCS-Modul Adaptive Lenkung (RCS-ADL), which sends suggestions to the locomotive driver concerning the optimal speed that would result in fewer stoppages and applying optimal speed from energy saving perspective. This concerns especially railways tracks utilised by numerous actors. Application of RCS-ADL in 2000 trains in Switzerland results in energy savings of 200 MWh per day. In addition, also wear to the rolling stock is reduced improving efficiency as the system ages.
By ensuring efficient driving practices and network usage throughout the period of service, the energy efficiency of rail systems can be maintained or increased to ensure emissions savings.
Switzerland is known for having an efficient rail network and is continuing to make improvements yearly. Starting in 2015, Swiss Federal Railways AG (SBB) started charging locomotives equipped with individual meters only for actual energy consumption. Additionally a project which switches off heating to full carriages during peak hours to decrease energy demand recently won the Watt d’Or prize for its innovative approach to flexible consumption management. SBB also uses an adaptive control program to ensure that trains are travelling at optimal speeds to reduce waiting time, increase efficiency, and avoid conflict between trains which would increase energy demand and reduce efficiency.
Japan is perhaps the pinnacle of high speed rail, and the East Japan Railway Company (JR East) has made significant investment when it comes to promoting energy efficiency in its network. JRR East implemented an energy saving policy which centres around four pillars: increasing regenerative energy utilisation, increase renewable energy options at stations, manage energy usage at stations, and implement battery operated trains where possible. This comprehensive plan aims to meet reduction targets of -25% energy consumption and -40% carbon emissions by 2031.