Jubilee and Metropolitan Line in Harrow

Plenary on 2011-11-09
Session date: 
November 9, 2011
Question By: 
Navin Shah
Labour Group
Asked Of: 
Boris Johnson (Chair, TfL) and Sir Peter Hendy (Commissioner, TfL)


My constituents who live next to the Jubilee and Metropolitan Lines have raised their concerns about the noise level coming from the tracks at night when unscheduled engineering work is taking place. London Underground suggested that more trees be planted along this section of the line in Harrow to act as an acoustic barrier. What plans do you have to implement this?


Answer for Jubilee and Metropolitan Line in Harrow

Answer for Jubilee and Metropolitan Line in Harrow

Answered By: 
Boris Johnson (Chair, TfL) and Sir Peter Hendy (Commissioner, TfL)

I do not believe that London Underground (LU) has ever suggested it would plant trees for this purpose. In fact, trees are an ineffective acoustic barrier against noise from engineering works and LU therefore has no plans to plant trees for this reason.

Studies show that for trees to be effective at reducing noise they would need to be densely planted to a depth of at least 10-15 metres close either to the source of the noise or the receiver. The embankments bordering the Metropolitan and Jubilee lines are generally narrow and steep sloped with few sufficiently wide sections to allow for this kind of tree planting. In addition, LU's engineering standards prevent the planting of trees near fences, trackside cables or retaining structures, for safety reasons. High water demand trees can contribute to embankment instability in clay soil types found on the embankments.

LU notifies residents whenever it can about planned engineering and maintenance works where there is a risk of noise disturbance. There are occasions where this is unfortunately not possible due to the short-notice, safety-critical nature of the works.