Every year, British commuters endure delays caused by the accumulation of leafy slush on train tracks, particularly in late fall when leaf loss is coupled with high levels of moisture in the air or on the ground.

Wet leaves pose a safety challenge for train operators, potentially doubling the breaking distance. Leaves also can cause signaling issues or "disappearing trains" on the rail control systems. This is due to the electrically insulating effect of the leaves, which can prevent operation of track circuits.

However, leaves on the line are only an issue when they are mixed with moisture or dew, creating a slippery, Teflon-like substance.

Leaves on railway lines can create a slippery, Teflon-like substance. Image credit: PixabayA technology developed by Lee Chapman, professor of climate resilience at the University of Birmingham, UK, uses low-cost sensors to measure the level of moisture on railway lines at potentially thousands of sites across Britain's rail network. By linking this data with a leaf-fall forecast, operators can identify where and when the risk is greatest. This allows for a more precise and efficient use of automated treatment trains, which can clear the lines before rush-hour trains set out.

Chapman says that while leaf loss and damp conditions can largely be predicted—and despite automated treatment trains working around the clock from October to December—a windy, rainy night can cause havoc for commuters.