Will battery-electric trains replace diesel trains and are they really safe?
In the search for more sustainable alternatives, battery-powered trains are emerging as a promising option to replace the diesel engines that dominate the UK’s railways. With a focus on energy efficiency and emissions reduction, these trains could mark a new era in rail transport.
Why battery-powered trains?
Trains in the UK currently run on electric power supplied by overhead lines or with on-board diesel generators on non-electrified tracks. The latter option has for decades been the standard solution for network sections not connected to electrification. However, maintenance and expansion of electric cable infrastructure is costly, leaving large portions of the rail system with limited sustainable options.
Battery-powered trains are emerging as a cost-effective hybrid solution to this challenge. For example, Hitachi has developed a “tri-mode” train that combines battery power, overhead line electricity and diesel generators, enabling fuel consumption to be reduced by up to 50% on routes without electrification.
Technology behind battery-powered trains
Today’s battery-equipped trains use technology similar to that of electric vehicles (EVs). Hitachi’s test model replaces one of the diesel generators with a set of 16 lithium batteries, which can be recharged while the train is operating on electrified tracks or in stations in 10 to 15 minutes.
These trains have the ability to automatically switch between different energy sources, maximizing efficiency. In addition, it has been proven that existing electric trains can be retrofitted with batteries to make them more sustainable, reducing the need to replace entire fleets.
What makes them viable now?
Although battery-powered trains are not a new concept, recent advances have made them a practical alternative. The first lithium battery-powered trains entered service in Japan in 2016, but interest in the UK has grown thanks to improved battery capacity and government support towards greener transport.
For example, the UK government aims to achieve net zero carbon dioxide emissions by 2050. In this context, the transition to all-electric or hybrid trains is a natural step.
Even so, limitations remain. Currently, batteries do not have the range to cover all routes without electrification. For example, Hitachi’s test train can run 70 km on batteries, sufficient for routes between London and Oxford, but insufficient for others such as Crewe-Holyhead.
Are battery-powered trains safe?
Safety is a priority in the development of this technology, especially considering the risks associated with lithium batteries. Although these batteries are very safe when handled correctly, they can experience a phenomenon called thermal runaway in the event of severe damage, which can lead to fires that are difficult to control.
However, tests conducted by Hitachi have shown that these batteries are highly resistant. To ensure passenger safety, measures have been implemented such as:
- Heat shields to prevent a fire in one cell from affecting other cells.
- Cooling systems to maintain an optimum temperature in the batteries.
- Advanced software that monitors and regulates cell operation.
In addition, the trains are designed so that damaged units can be safely evacuated and removed from the tracks without compromising the integrity of the passengers.
The future of rail transport
Although battery-powered trains still face technical and economic challenges, they represent a key transition to a more sustainable rail network. Hybrid solutions, such as tri-mode trains, are intermediate steps towards full electrification, while battery technology continues to improve in terms of capacity and weight.
With companies like Hitachi and Siemens leading the way, the rail industry is at a tipping point that promises not only to reduce environmental impact, but also to modernize existing infrastructure at more manageable costs.
