Commuters saved from ‘leaves on the line’ by engineering breakthrough

Undated handout photo issued by University of Sheffield, showing dry ice being blasted onto railway lines across northern England in a trial aimed at removing leaves more efficiently than current methods. The trial involves pellets of dry ice being fired in a stream of air from a passenger train onto rails, making leaves frozen and brittle. The dry ice then quickly turns back into gas, causing it to expand and destroy the leaves. Issue date: Monday October 4, 2021. PA Photo. See PA story RAIL Leaves. Photo credit should read: Ruby Kempka/University of Sheffield/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder.
Railway lines across northern England are involved in a trial aimed at removing leaves more efficiently than current methods. (Credits: PA)

Every autumn rail passengers face disruption and delays because of leaves on the line.

But now a new way of clearing the fallen foliage has been discovered and it could have huge implications for passengers.

It works by firing pellets of dry ice onto the rails to make the leaves frozen and brittle.

The technique, developed by Sheffield University, then sees the chemical compound turn back into gas — causing it to expand and destroy the leaves.

Engineers say the latest method covers greater distances and leaves no residue, which can damage rails and train wheels.

The system can also be used on the same stretch of railway more than once a day.

Train operator Northern is testing out the idea on several stretches of railway in the north of England.

Undated handout photo issued by University of Sheffield, showing dry ice being blasted onto railway lines across northern England in a trial aimed at removing leaves more efficiently than current methods. The trial involves pellets of dry ice being fired in a stream of air from a passenger train onto rails, making leaves frozen and brittle. The dry ice then quickly turns back into gas, causing it to expand and destroy the leaves. Issue date: Monday October 4, 2021. PA Photo. See PA story RAIL Leaves. Photo credit should read: Ruby Kempka/University of Sheffield/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder.
The trial involves pellets of dry ice being fired in a stream of air from a passenger train onto rails, making leaves frozen and brittle. (Credits: PA)

If successful, it will be rolled out countrywide by 2023.

Professor Roger Lewis, who is leading the development of the new method, said ‘This technology will make a step change in train performance during autumn, improving safety.

‘It will provide more predictable braking and traction than current technology, and will help to improve train performance, reduce delays, increase passenger satisfaction and support the use of new technologies to enable greater network utilisation of the UK’s railways.

‘It will be great for passengers, but also for all the train operators and Network Rail as well. It will make their lives much easier.’

Leaves on the line: Why are they such a problem?

Undated handout photo issued by University of Sheffield, showing dry ice being blasted onto railway lines across northern England in a trial aimed at removing leaves more efficiently than current methods. The trial involves pellets of dry ice being fired in a stream of air from a passenger train onto rails, making leaves frozen and brittle. The dry ice then quickly turns back into gas, causing it to expand and destroy the leaves. Issue date: Monday October 4, 2021. PA Photo. See PA story RAIL Leaves. Photo credit should read: Ruby Kempka/University of Sheffield/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder.
Autumn-related issues cost the railway industry approximately £345 million every year. (Credits: PA)

Some 10 million trees line Britain’s railway, and thousands of tonnes of leaves fall onto the tracks every autumn.

When trains pass over the leaves it creates a slippery layer, with a similar effect to black ice on roads.

This leads to delays as trains must run at a reduced speed, accelerate slower and brake earlier.

According to Network Rail, a build-up of leaves on the tracks can also cause delays by forming a barrier between the train wheels and the electrical parts of the track that help pin-point where trains are.

When operators aren’t sure exactly where a train is, the trains behind will be delayed at red signals until the first train’s location is established so that control rooms can be confident there is always a safe distance between trains.

Currently leaves are cleared by 61 special trains, which deploy high-pressure water jets and a gel containing sand and steel grains to assist with braking.

Rob Cummings, seasonal improvement manager at Northern commented: ‘We’re very excited to test this new technology during the autumn period.’

Undated handout photo issued by University of Sheffield, explaining how a new leaf-clearing technique works by blasting dry ice onto railway lines. The trial involves pellets of dry ice being fired in a stream of air from a passenger train onto rails, making leaves frozen and brittle. The dry ice then quickly turns back into gas, causing it to expand and destroy the leaves. Issue date: Monday October 4, 2021. PA Photo. See PA story RAIL Leaves. Photo credit should read: University of Sheffield/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder.
The dry ice quickly turns back into gas, causing it to expand and destroy the leaves. (Credits: PA)

‘One of the biggest risks to our performance during October and November is leaves on the line, but by helping to develop new technology we aim to deliver the very best service for our passengers.’

Autumn-related issues cost the railway industry approximately £345 million every year.

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