Relief from leaves

No more leaves on line?

We could be seeing an end to the age old problem of dreaded leaves on the lines causing Tube delays thanks to some nattily named software.

The Adhesion Controller's Condition Assessement Tool (try saying that after a few beers) "calculates the likelihood of leaf fall problems, by examining data such as the risk of leaves falling, the quantity and condition of leaf litter and the resultant leaf litter mobility, moisture levels, and a real-time update of general weather conditions – in particular those which lead to light rain and moisture." Not sure what would happen to the software if there was the wrong type of wind, or wrong type of rain, or stickier than usual leaves though.

But even when bad weather is predicted will anyone from London Underground take any notice? Remember the very accurate snow forecast that still caught the Tube out earlier this year. Engineers will still have to decide whether to mobilise early morning "leaf squad" - a team of engineers who spray a gritty substance to break down the leaves.

ACCAT will initially be used on the Central Line "70% of the 74 km Central line is in open sections where leaf fall is a continuous threat to the smooth running of the line during the autumn 12-week period from October to December.

The problem arises when fallen leaves are rolled into a layer of crushed debris forming a coating as tough as Teflon. When damp, the layer is extremely slippery and adhesion is reduced below the levels on which signal braking distances are calculated, so ATO (automated train operating) has to be suspended." said Metronet

However the predictive system may be extended to the Metropolitan line, and mainline train operators have expressed interest in using the system as well.