Environmental impacts » Case study » Noise

Less noise on the tracks

Noise monitoring on the Northern line has proved that our track renewal work does not just give passengers a more reliable and comfortable journey. As clattering trains become a thing of the past, people living close to the lines are enjoying the peace and quiet.

“We measured noise levels on the Northern line between Totteridge & Whetstone and Woodside Park stations before and after we carried out enhanced track renewal work in December 2005,” explains Environment Adviser Shane Mc Entee. “This identified an average and peak reduction of approximately ten decibels – reducing the noise levels significantly. We monitored noise at the same locations three, six and 12 months afterwards and at 12 months an average and peak reduction of eight decibels had been maintained.”

“Because the new track form sits on resilient rubber pads and a firmer base with new ballast and rail, noise is reduced,” comments Delivery Manager Paul Watson. “Usually, trains make a noise as they go from one rail to the next, but with the new type of rail, this is reduced.

“This has brought benefits around the network. Once we had replaced a section of the northbound track, local residents commented on the huge difference it had made and asked if we could do the southbound, too.”

Tubevac’s star performance

A giant new industrial vacuum cleaner brought into operation in September 2005 became such an excellent asset for Tube Lines in 2006 that we ordered another one. It has increased productivity on our track upgrade activities by 300 per cent – and reduced noise levels, too.

The Tubevac, made by the Swedish company DISAB, is a vacuum excavation machine used to hoover up ballast and silt, a job that was previously carried out by men using shovels, which was much noisier and took much longer. Tube Lines has been using it mainly for replacing compacted lumps of ballast which cause trains to bump, creating discomfort for passengers and increasing rail and wheel wear.

“The Environment team measured noise levels of the Tubevac and compared them with noise measurements taken when the work is done using traditional methods,” says HS&E Adviser Paul Cooper. “We found that the Tubevac has reduced peak noise levels by eight decibels.”