Environmental impacts » Case study » Wildlife

Cutting tree felling to a minimum

As new computerised signalling systems are installed on the Jubilee, Northern and Piccadilly lines, patterns of train acceleration and deceleration will change. However, we are already having to change the way we control trackside vegetation, in advance of the installation of the new signalling.

“Traditionally, trains brake and accelerate at defined points, making it easy to identify areas where trees have to be felled to ensure minimum leaf fall and therefore maximum traction,” explains Steve Judd, Tube Lines Environmental Asset Manager. “With the new system, these acceleration and braking patterns will vary far more, making it harder to pinpoint priority areas for vegetation clearance.

"We carried out a review of the track in standard 250m sections on the Jubilee line in 2006 to assess the extent of vegetation requiring clearance in advance of the signalling upgrade, but found that only a small proportion of each section would need to be cleared,” he adds. “So we reviewed the survey using 50m sections which has eliminated any unnecessary tree felling. This has saved trees, associated habitat and wildlife.”