Why do leaves on the line cause problems for trains?

A train undergoing wheel repairs at the Canton depot

The idea of leaves on the line causing delays and cancellations is sometimes met with amusement, and more than a little frustration.

But rail companies say the problem can be as dangerous as black ice on our roads.

So what is the problem?

  • Leaves are swept onto the track by wind or passing trains.
  • After rain falls, the trains crush the leaves under great pressure
  • The compressed leaves stick to the rails, causing trains to slip, as well as damaging their wheels.
  • Left unchecked, this wear and tear can damage the tracks too.

At Arriva Trains Wales' huge Canton rail depot, Ryan Williams explains what the consequences can be.

A train 'tyre' can get damaged just as your car tire gets damaged.

If they suffer too much damage we have to change the whole wheel sets, which means a train out of traffic for two days.

We've got engineers working around the clock keeping this place running!

The guys do a terrific job turning the trains around.

– Ryan Williams, Head of Engineering, Arriva Trains Wales

So far this season, 35 trains in the fleet have suffered damage to their steel tyres.

At the depot, a giant lathe is used to 'skim' the metal off the tyre to remove any burrs and indentations.

The lathe skimming metal off a train's wheels

Train driver Gareth Derry knows the problem all too well.

"There's no bigger challenge for us than the autumn season" he says.

Gareth Derry driving the train

He accepts that the knock on effects from poor weather are inevitable, but says the safety of passengers is "a core principle".

If you think about how hard it is to stop a car in the winter, trying to bring a train under control in those sort of condition is really challenging.

It's about being prepared - knowing the sort of places where we're going to encounter the worst conditions - and breaking earlier and lighter so not to make the train skid at all.

– Gareth Derry, train driver
  • Below: A railhead treatment train sprays water onto the tops of tracks under high pressure to clean them

So what else can be done to limit the problem in the first place?

Network Rail's Chris Pearce and his team are working hard cutting back trees and vegetation along a stretch of the line near Whitchurch, Cardiff.

They specialise in making sure the rail infrastructure is safe and efficient, whatever the weather may bring.

Network Rail teams tackling trees beside the railway line

He says collaboration between his organisation and train operators in tackling the problems associated with autumn and poor weather have improved.

With Arriva Trains Wales, we've put a plan in place to make sure we target locations to carry out devegetation work where it causes the biggest problems.

We are careful in terms of how we remove it, but the first priority is safety, to make sure that the trains keep moving

– Chris Pearce, Network Rail

Train companies say they are better prepared than ever to anticipate and tackle the problems bad weather and environmental conditions can cause.

That's not necessarily great comfort to passengers facing delays and disruption, but operators stress that their safety is ultimately the priority.

  • Watch the Wales at Six report below:

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