Will new battery-powered trains exchange diesel, and are they protected?

Quickly battery-powered trains could possibly be coming to a station close to you.

Because the UK’s fleet of diesel engines approaches retirement, producers wish to exchange them with environmentally-friendly alternate options.

Trains at present draw energy from overhead electrified wires or, on traces with out these wires, from onboard diesel turbines. Many trains are able to working from each energy sources and swap between the 2.

Battery-powered trains would save rail operators the price of putting in overhead wires on unelectrified tracks, that are discovered all through the UK.

At Hitachi’s manufacturing unit in Newton Aycliffe, north-east England, testing has simply completed on a brand new “tri-mode” prepare, through which one diesel generator has been swapped for lithium batteries. This enables it to make use of as much as 50% much less gas when working on traces with no overhead wires.

Primarily based on this trial, the corporate can also be planning a prepare mannequin with no diesel turbines in any respect, which it hopes might be able to travelling as much as 90km (56 miles) on unelectrified stretches of observe – with a view to all the rail community going diesel-free.

Siemens can also be creating its personal battery-only trains at its manufacturing unit in Goole, East Yorkshire. The corporate says it’s anticipating orders for greater than 600 trains from operators together with ScotRail, Nice Western Railway (GWR) and Transport for Wales. GWR additionally examined its personal battery prepare earlier this yr.

Solely battery-powered trains are already working in Japan and Germany, however UK specialists say they might pose distinctive fireplace security challenges.

Hitachi engineers inform the BBC, although, that it has finished in depth testing on the batteries to make sure passengers could be protected in an emergency.

Present diesel-electric trains are designed to attract their energy from overhead traces on electrified sections of observe. Elsewhere, they use diesel turbines housed beneath their carriages.

Hitachi’s new prepare replaces one among these diesel generator models with 16 batteries, like these present in electrical automobiles (EVs).

It says the trains can swap between energy sources routinely, and that the tri-mode model would primarily use its batteries in stations and concrete areas.

Hitachi says these batteries can recharge whereas the prepare is travelling on electrified tracks, or in 10-Quarter-hour whereas stationary.

The corporate says current diesel-electric trains may be retrofitted with batteries to economize.

The primary prepare to rely solely on lithium batteries went into service in 2016 in Japan – greater than six many years after some restricted use of trains in Scotland powered by lead-acid batteries. So why is the lithium battery possibility solely now being developed within the UK?

Koji Agatsuma, Hitachi Rail’s technical chief, who oversaw the corporate’s battery prepare undertaking, says there’s now curiosity within the UK due to a mixture of technological enchancment and a change in political local weather.

He says the brand new authorities’s imaginative and prescient is for trains to be “cheaper, greener, extra dependable”, whereas batteries are getting smaller and extra highly effective.

But even now, limitations stay.

Hitachi designed the tri-mode prepare as a result of its batteries weren’t but capable of final lengthy sufficient to cowl all sections of unelectrified observe within the UK.

Extra areas of railway may be electrified, however that is expensive: in 2020, Community Rail estimated electrification would price £1m-£2.5m per kilometre of observe.

Siemens says to run its battery-powered trains on the UK’s rail community, small sections of observe would have to be electrified, and fast-charging factors positioned alongside prepare routes.

Hitachi’s take a look at prepare was capable of journey 70km (44 miles) utilizing its batteries alone. This might work for providers between London and Oxford or Hull, because of the quantity of electrified rail on these routes, however it could be unable to run the total size of the road between Crewe and Holyhead, for instance.

And although it was capable of journey 135km (84 miles) utilizing diesel in addition to batteries, this was on comparatively flat testing observe. Routes equivalent to these served by TransPennine – which leant Hitachi the take a look at Class 802 prepare – have inclines which require extra vitality, shortening the general distance it may journey unaided.

Jim Brewin, Hitachi Rail’s UK and Eire chief, says the federal government’s intention to chop the nation’s carbon dioxide emissions to internet zero by 2050 means absolutely battery-powered trains are the course the trade is shifting in, with hybrid trains a stepping stone on the best way.

He says that as cells get lighter and extra highly effective, the corporate can swap them out for newer fashions to enhance efficiency. Its current testing demonstrated current trains may be modified to go full or half battery-powered.

Consultants in lithium batteries say that, when utilized in highway automobiles, EV batteries are at the very least 20 occasions much less prone to catch fireplace than diesel or petrol automobiles.

Hitachi’s prepare makes use of Nissan Leaf cells, which have been concerned in 16 fires within the 14 years they’ve been utilized in highway automobiles, in response to EV Hearth Protected, which gathers knowledge on battery fires world wide. That is out of greater than 500,000 cells which have been bought worldwide.

“Managed correctly, lithium batteries are very protected,” says Jon Simpson, a former firefighter turned fireplace security marketing consultant.

However when lithium batteries are corrupted, they will expertise thermal runaway – which means a cell undergoes uncontrollable temperature rises, making a hearth exhausting to manage and extinguish.

The form of “catastrophic occasion” that would trigger one thing like this is able to be a crash or a derailment through which a cell is broken, says Jon Hughes, managing director of UK Hearth Coaching.

However Euan McTurk, a marketing consultant battery electrochemist, says Nissan Leaf cells are “much more strong than folks give them credit score for”.

He says: “For them to catch fireplace, it could take some spectacular lancing of the particular cells themselves, which might imply going by a really sturdy exterior construction.”

A part of Hitachi’s testing was to intentionally destabilise a cell, together with piercing it and overheating it, says Chris Dautel, senior electrical engineer on the producer.

He provides that Hitachi has positioned a warmth protect round every cell to stop the difficulty spreading to different cells, which means “no hazard to passengers in [a] case of thermal runaway”.

The prepare can also be fitted with a cooling unit on the roof to control the batteries’ temperature, and the corporate has developed software program that screens and regulates the cells.

The pressing response to a lithium battery fireplace is to flood the cell with as a lot water as attainable to chill it down, says fireplace security marketing consultant Mr Simpson, which is probably not viable relying on the place the hearth happens.

“Tunnels are most likely the riskiest space in a rail setting,” says Graham Kenyon, {an electrical} engineering marketing consultant. “In case you get a hearth, most likely the worst issues to take care of once you’re evacuating individuals are smoke and fumes, vapours, gases which might be poisonous.”

In some instances, it’s safer for the hearth brigade to go away the battery to burn itself out. However leaving a prepare on the observe may pose a significant disruption.

Dautel says {that a} carriage with a battery fireplace may nonetheless be moved out of the best way, even whereas burning, such was the effectiveness of the hearth barrier across the cells.

“Within the case of incidents, we’d evacuate the passengers, however they wouldn’t see something,” he says.

As every unit operates independently, he provides, the prepare would nonetheless be capable to transfer itself utilizing batteries on different carriages – or be pulled by one other prepare.