Every autumn, thousands of tonnes of leaves fall on train tracks across the UK. When wet, these leaves stick and become compacted by passing trains, forming a slippery layer. Our drivers need to allow extra time and distance for more gentle braking and our trains may take longer to accelerate during this period. Our Autumn Timetable comes into effect on 7 October on the routes below. Please remember to check your journey for any changes.
What's the problem with leaves on the line? Leaves falling onto the track are dragged under passing trains. They're crushed at a force of over 30 tonnes per square inch into a slippery paste. When it's wet, this slippery coating covers the rail and sets to form a hard Teflon like coating. The slippery rails make it difficult for train wheels to grip on the track.
Why does this cause delays?Trains rely on friction between the wheels and rails in order to get grip, particularly while accelerating and braking. Because the top of the rails become slippery it can take trains longer to pull away from stations. They also have to apply their brakes earlier when they stop.
What is being done to clear tracks and reduce delays?Out on the tracks A lot of work goes on to tackle the perennial problem of leaves on the line. Network Rail ensures there are dozens of specialist teams out on the tracks across the UK, clearing leaves 24/7. They also run special trains along affected lines that spray a special gel on tracks to provide more traction. Driving techniques and an Autumn TimetableWe train our drivers to give them the skills they need to cope with autumnal train driving conditions and, crucially, we make some small changes to our timetable to allow extra time and distance for more gentle braking and acceleration.
Much of the railhead cleaning is now done using water cannons fitted to the MPV engineering vehicles. Water cannon treatment has the advantage that it doesn't leave a sticky residue for the leaves to adhere to. Also it's cheaper than sandite.....
Sandite is still used in areas of severe leaf contamination, but as I understand it is mainly done by manual application on really bad spots for leaf fall.
For a long time I have managed to avoid Network Rail public information videos, this one is awful; dumbed down just doesn't come into it.... Just about the right level for CBBC.
No mention of the layer of crushed leaves interrupting track circuits and therefore interrupting train detection leading to signalling delays. This is the real problem for the railways as the trains "dropping off" track circuits causes all sorts of problems where the signalling system detects a train which hasn't worked through the planned sequence of track circuit detection and drops back to safe mode and puts all nearby signals back to red.
No mention of contamination of wheels affecting braking.
No mention of how the railhead is cleaned using water cannons.
No mention that disc brakes don't clean the wheel tread in the way that traditional clasp brakes used to. ( But that means admitting that modern isn't always the best solution. Other TOC's have fitted "scrubber" brake blocks to clean wheel rims on their class 158 units. )
To SWR: sorry for the grumble, but I do feel that most travellers and users of this forum should have technical problems explained. Most users on here have a good level of literacy and should be able to comprehend most of the concepts which need to be explained. There is nothing wrong with asking "what does that mean?"