This is the season for the railways to grind, or rather slip, to a halt. It comes as no surprise that leaves fall off the trees in autumn, but for years train services were plunged into chaos by dead leaves on rail lines.
The problem is especially bad after a gale has blown down lots of leaves in heavy rain. When the leaves drop on to rails, the train wheels mash them into a sludge that sets into a thin, slippery coating, and so the train loses traction — rather like ice on roads.
The situation was very bad seven years ago when a big storm brought down cascades of leaves. And Eurostar train services also came to a halt when sea spray was blown far inland in France and encrusted overhead power cables with salt.
The solution to the leaves on the line has been to blast the rails clean with water cannons, or a gritting mixture known as sandite, to give the trains more grip. In one case, though, excessive sandite created such intense friction on the wheels that one train caught fire.
This year Network Rail has taken drastic measures to reduce the leaf problem. It has pruned the trees alongside railway lines to prevent leaves from falling on the lines, although this has destroyed woodland on the embankments that provided important corridors for wildlife. Another, less destructive, measure has also been taken — some train operators have introduced a slower timetable in the autumn.