Central line rail noise
Request ID: FOI-1279-1718
Date published: 06 September 2017
You asked
On the central line, eastbound, between Liverpool Street and Bethnal Green, there was a seven second section of track which used to make a hellish noise whenever the train went over it. It's recently been quietened, thankfully. However, under the terms of the Freedom of Information Act 2000, I should like to know the following information:
a) The cause of the noise
b) What measures were taken to reduce the noise
c) Any decibel readings which were taken before it was quietened (including the loudest measurement)
d) How often this spot of track will be monitored, and any further action that will be taken
Many thanks for your time.
We answered
TfL Ref: 1279-1718
Thank you for your request received by Transport for London (TfL) on 29 August 2017 asking for information about noise on the Central line.
Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy. I can confirm that we hold some of the information you require. You asked:
On the central line, eastbound, between Liverpool Street and Bethnal Green, there was a seven second section of track which used to make a hellish noise whenever the train went over it. It's recently been quietened, thankfully. However, under the terms of the Freedom of Information Act 2000, I should like to know the following information:
a) The cause of the noise
The rail in this area is prone to corrugation (a type of wear) which can lead to increased levels of noise in properties above our tunnels. To mitigate this we initially installed 125m of shock absorbent track fixings (Pandrol Vanguard) to the eastbound track, close to Bethnal Green station. At this location however, the combination of corrugated rail and these fixings caused the rail to emit a screeching noise in the tunnel as the train travelled over it.
b) What measures were taken to reduce the noise
To reduce this noise, we removed the fixings and replaced the corrugated rail with new, harder steel rail that’s more resistant to wear of this kind. We then re-installed the fixings, to ensure maximum noise reduction for affected residents.
c) Any decibel readings which were taken before it was quietened (including the loudest measurement)
See attached readings on the rail section in question. The loudest noise measured in the tunnel was 105.6dB(A).
d) How often this spot of track will be monitored, and any further action that will be taken
The last noise monitoring in this area was undertaken on 23 August 2017. As part of our work to ensure a safe and reliable service, we patrol all lines to check the condition of the track at 72 hour intervals. We will also continue to monitor the rate of corrugation at this location and will be carrying out rail grinding to control or reduce noise and vibration as necessary.
If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.
Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.
Yours sincerely
Sara Thomas
FOI Case Management Team
General Counsel
Transport for London
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