Did you know that leaves on the track can pose a serious safety threat to trains and cause major disruptions to your rail journeys?
Here’s how we’re tackling this problem through innovation …
The problem
Leaves on the track can delay your journeys – particularly in the autumn.
Fallen leaves can make the top layer of the track – or the rail head – slippy. This can then make it harder for trains to move safely along the track as the train wheels struggle to maintain contact with the rail. It can cause trains to slip and even derail.
Trains then must move slower along the slippery track to counter this. They may also have to brake and accelerate more slowly and for longer to avoid slipping.
All this can lead to train delays and disruption. In extreme cases, trains may come to a complete standstill until the track has been cleared and it’s safe to move again.
For example, in October 2022 a freight train came to a halt on a busy TransPennine route due to leaves on the track. It took nine hours to clear the track and get the train moving again.
What’s low adhesion?
Adhesion is the term used to describe how well the wheels of a train can roll on the track. Low adhesion occurs when the wheels struggle to roll smoothly on the track.
In Britain, leaves falling on the track in the autumn often cause low adhesion. But other contaminants on the track like rust and grease can also cause it.
Improving low adhesion using water
Research in labs has shown adhesion improves if we make the rail head wet in low adhesion conditions such as when there are leaves on track. The theory is that trains can once more run smoothly along the line.
We also see this in the real world when train wheels glide more easily along the rail during and after heavy rainfall despite leafy conditions.
The trial
We worked with train operator Northern Trains to test these lab findings on the railway. Together we trialled a unique watering system – the Water-Trak system – in the autumns of 2021 and 2022.
The Water-Trak system works by applying a small amount of water from the underside of the train onto the rail head during low adhesion conditions. The Water-Trak system wets the rail head to create the rainy day conditions that allow the train’s wheels to glide safely along the track.
We trialled the Water-Trak system on two electric trains working around the northwest of England in autumn 2021.
We followed this the next autumn with a trial of the system on two diesel trains that ran in Yorkshire.
Results
The trials’ results were positive, suggesting Water-Trak is an effective way to deal with leaves on the track.
The trains using this system were able to run safely along the rail even during leafy conditions. It also helped them brake faster, preventing train delays.
For instance, the stopping distances for the two electric trains trialling the system in autumn 2021 reduced by more than 12% in low adhesion conditions.
The future
We’re now looking at using the Water-Trak system across a whole fleet of trains to test it further.
We’ll look into using the system more widely across Britain if these extra trials go well. Ideally, Water-Trak could reduce the disruptions caused by leaves on the line – leading to fewer train delays and improved journey times for you.
