Autumn Leaves

[Anonymouse]

Has anyone seen the latest gem from the railway companies? I saw a poster on the Bolton-Manchester train which gave a pseudoscientific explanation as to why leaves on the track cause delays. Allegedly certain types of leaf can, when subjected to pressure between a train's wheels and the track, form a Teflon-like coating which, of course, makes the tracks slippery and therefore the trains have to slow down on certain turns. Hence the delays.

Oh, come on!

[LSainsbury]

Errrrr our saucepans have a Teflon coating so stuff you put in them doesn't stick....so in theroy the trains should go faster! ROFL!!! :-)

not so far fetched, apparently ?

Leaves on the line are a problem that affects all countries with deciduous trees, and no universal solution has yet been found. The phenomenon occurs because the train wheel exerts 40lbs per square inch of pressure on the rail, generating heat, which bakes the lignin in the leaves on to the rail so firmly that it would take a knife to scrape them off. This "black ice"of the rails means trains lose traction and braking ability and can overshoot signals and stations.

from http://www.guardian.co.uk/g2/story/0...ticle_continue

[Woolly One]

Sorry, but they are right (if you believe the 'expert'). Article is from from 2002 - still relevant it appears.

http://physicsworld.com/cws/article/print/5399

The problem arises whenever leaves from trees bordering the track fall close to the rails, where they are swept up by the turbulence caused by passing trains before being crushed under the wheels of the carriages. The leaves are pounded into a hard, black, shiny Teflon-like substance that is difficult to remove, even with a sharp knife. Horse chestnuts and limes are the biggest culprits, with their leaves having the highest "squidge factor".

Cleaning the tracks
In the old days of steam trains, leaves on the line were never a problem for Britain's railways. Trees bordering lines were regularly cut back to prevent sparks from igniting the foliage. But as diesel and electric trains gradually replaced steam engines, the trees were allowed to grow so much that they began to encroach on the line. It also became common for trees to be planted to help cut train noise.

IMO if they had kept up the 'good practice' of cutting back in the first place, then they wouldn't be in this situation every year

p.s. I would love to know how you work out the squidge factor