Leaves on the track – Q&A with Josephe

We spoke with Josephe about why leaves on the track can cause disruption and what’s being done about it. Josephe is in charge of the leaf fall mitigation programme at London Underground.

What does it mean when delays are caused by leaves on the line? 🍃

Leaves falling onto train tracks is an issue for railways across the country. It might sound strange but leaves on the track can cause severe disruption if measures aren’t taken to prevent it. 🛤

When leaves fall from trees onto train tracks, they’re crushed into mulch. That mulch then sticks to the tracks, and makes the rails slippery. Trains have to accelerate and brake more carefully and, when the rail is particularly slippery, it can cause the trains to skid while braking. The effect is similar to what would happen if a car was braking on an icy surface. ⚠️

What effect does that have on the trains?

When trains skid, it means that they take longer to stop than they should. That affects stopping at signals and at platforms, making it more difficult to run a reliable service and affecting safety. Another problem is that train wheels are made of metal. So when they skid, part of the wheel is worn away and it becomes misshapen! Trains running with misshapen wheels aren’t safe, so the whole train needs to be taken out of service for repairs. 🧰

What parts of the Tube network are affected by this?

This tends to be more of a problem in more rural areas, away from the tunnels in central London. Areas like the northern part of the Central line and the Piccadilly line between Rayners Lane and Uxbridge are particularly affected. This is because the rails are exposed and the trains are older. The new, modern trains on the Metropolitan and District lines feature technology that helps trains deal with these conditions. The Piccadilly line, for example, has much older trains that struggle far more with the conditions, causing more delays than on other lines.

What can you do to help stop these delays from happening?

We’ve been working hard all year to prepare for this time of year. We’ve spent over 95,000 hours removing trees in particularly affected areas. During the season we collect leaves from the network around the clock. Last year over 70 tonnes of leaves were taken away from the tracks during the season! 🍁

We also run five special trains across the network, called rail adhesion trains or RATs. These trains apply a special gel that helps wheels stick to the rails and avoid skidding. These run in areas where the rails become particularly slippery and operate every day during this time of year. 🚆

As well as these measures, we use specialised weather forecasts to tell us when the worst times will be for trees shedding leaves. This allows us to warn drivers ahead of time that they need to adjust their driving techniques. We can also send teams out to try and help the problem before it becomes too bad. 👌

What effect will this have on customers?

We’re running special timetables across the network in order to try and keep the service as regular as possible. Despite this work, there might still be some delays to your journeys. But we’re doing everything we can to reduce those delays and to make sure that the Tube is as safe and reliable as you expect it to be. 👩‍🔧