In this episode of my decade-long quest to correct popular British misconceptions, I wish to turn to one of my most geeky obsessions: trains. In particular, I would like to address a particularly British obsession, which many take as a signal of the lapse of British know-how from its mid-Empire industrial-revolution heights.
This is, of course, ‘leaves on the line‘. Why – demand the British public – must timetables run five to ten minutes slower when there are more leaves on the ground? Why do no other modern countries suffer from these ills? And why does the railway take no action over this commuting scourge?
Let’s review the facts. ‘Leaves on the line’ don’t somehow overpower train engines, like riding a bicycle through the mud. It has nothing to do with train speed and everything to do with dangerous braking failures. As leaves build up on the rails, the train’s metal wheels start to slip over the rail surface, as if on a coating of grease. In 2010, a commuter train overshot Stonegate Station in Kent at 64 miles per hour due to a section of track with leaf build-up. Despite the full application of emergency brakes, the train came to rest only six and a half minutes and three miles later.
Leaving aside the collision implications of a train that won’t stop for three miles, low adhesion has another serious implication: wheel flats. When too much braking is used in low-adhesion conditions, the wheels lock and the friction heats the wheels where they slide over the track. The resulting hot-spot causes rearrangement in the crystalline structure of the wheel, resulting in deformation and flattening. These flat spots are inefficient and noisy, so wheels must be removed from the cars and – at great expense – machined smooth. In 2017, a gap in lathing capacity caused half of the Piccadilly lines’s cars to go out of service in late fall. Better to slow the trains than to take them out of service entirely.
And this is a worldwide problem. At one point, nearly a third of one New York rail company’s cars were out of service due to wheel flats. Every major metropolitan railway service in the northeastern USA has reported delays due to low adhesion. The most common methods for increasing adhesion – rail sanding, gelling, and washing, sometimes by dedicated rolling stock operating at night – are in use across continental Europe, just as they are in the UK. In Australia, a summer plague of crushed Portuguese millipedes on the tracks has recently caused millions of dollars of delays and at least one railway collision.
In her 2004 classic Watching the English, anthropologist Kate Fox identifies the ‘moan exception’ as one rare case in which the unwritten British social rules permit talking to strangers. When something is going wrong, particularly on the railways, we bond with strangers by commenting on it. ‘Late again?’ goes the conversation. ‘Typical! The wrong sorts of leaves!’
But when, at long last, we are again permitted to have those conversations, let’s think of the halving of leaf-related delays over the last twenty years; the ubiquity and persistent intractability of the issue; the increasing demand for short, fast trains, which are particularly prone to low adhesion; and the hundreds of milllions of pounds spent on mitigation. Picture the night-shift worker driving a Sandite car over miles of track so you can get to work just ten minutes late. Hardly typical. Miss me with the moaning.
