Request ID: FOI-2972-2223 Date published: 09 March 2023
You asked
Dear Emma
My purpose in using the word 'any' was in recognition of the possibly unstructured information where you may search by terms and then retrieve one or more key correspondences to a subject rather than to mean 'all' to be including ancillary and extraneous information. It was my intention to help curtail effort to reduce the scope and I am sorry if 'any' was taken as "all".
As TfL similarly released the Pandrol Vanguard engineering assessments, TfL emerges from the public and visible Pandrol/Delkor switchover.
The answer given the GLA Mayor's questions on 21 June 2018 by TfL stated in "https://www.london.gov.uk/who-we-are/what-london-assembly-does/questions-mayor/find-an-answer/tube-noise-1-1"
"Noise and vibration reduction have been important factors in the development of a new trackform, which has been introduced since 2015. TfL do now consider the impact on noise and vibration prior to carrying out this type of work."
I was therefore reasonably asking if this has been done for the purposes of the track work locally to Chalk Farm.
As a learning organisation it might reasonably be expected for TfL to do things differently since this, and to evaluate noise and vibration likely to arise if fitting the resilient base plate on concrete (being a significant change), and to have working experience of the noise impact of the straightforward like for like rail replacements.
The specific concern is to find out if the known reports on this subject of track noise and vibration, already held by TfL, justify the proposed track work for mitigation of noise in relatively shallow stations, tunnels and track forms (as around Chalk Farm).
The public interest is clear: TfL asserts these types of repairs when discussing noise and vibration, so it is reasonable to ask "Ok, if that's what you are going to do, has it been assessed for noise and vibration?"
According to Britpave, acoustic performance of the resilient type track form is 'well documented'.
Where reports are held already and filed, a "wide retrieval' for all time was not meant to be sought, rather as a 'reports to TfL on file that meet similar scenario to that locally'.
The NLE project factsheet
https://content.tfl.gov.uk/nl-factsheet-f-web.pdf
cites prior noise risk & evaluation reports done in July 2012 on a section of the Victoria line, also used on the Jubilee, forming a basis for work, and the evaluation of the impact of the NLE. It seemtha small number of reports available are known of relevance to track work.
My request is limited to those reports held on file. The replacement of such track for noise reasons should not predate 2010.
If so either a new evaluation has been done specifically for here (which I think you at FoI confirmed, was not), or information is being relied on from prior similar work and would be readily referenced for this work (we are doing X after similar at Y).
Would TfL accept a request which is tighter in focus ?
as follows.
Pease provide a representative noise and vibration evaluation or noise and vibration risk assessment report produced for assessing similar track works to those proposed, i.e. (1) placing Resilient fixings on concrete baseplates, and (2) of replacing rails like for like, at a similar track location i.e. straight and with similar tunnel depth to that locally at Chalk Farm (~37m).
The cost line item should be a straightforward project retrieval and should be simple as an estimated planning rule of thumb eg £ per meter rather than to yield a possibly commercially sensitive cost.
The request for "any correspondence" is withdrawn.
We answered
TfL Ref: EIR-2972-2223
Thank you for your email of 13th February 2023 asking for information about noise on the Northern Line. Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy.
Specifically you asked:
“Pease provide a representative noise and vibration evaluation or noise and vibration risk assessment report produced for assessing similar track works to those proposed, i.e. (1) placing Resilient fixings on concrete baseplates, and (2) of replacing rails like for like, at a similar track location i.e. straight and with similar tunnel depth to that locally at Chalk Farm (~37m). The cost line item should be a straightforward project retrieval and should be simple as an estimated planning rule of thumb eg £ per meter rather than to yield a possibly commercially sensitive cost.”
TfL does not hold the requested information, as the request is based on an incorrect premise. You have specifically asked about the following, stating that such works are “proposed” at Chalk Farm:
placing Resilient fixings on concrete baseplates
However, we are not planning this type of work between Chalk Farm and Belsize Park.
of replacing rails like for like, at a similar track location i.e. straight and with similar tunnel depth to that locally at Chalk Farm (~37m).
Again, we are not planning this type of work between Chalk Farm and Belsize Park.
The works being carried out at Chalk Farm involve changing the rails from outdated bullhead to new flatbottom rail, using the existing sleepers (or occasional new timber sleepers if needed). The plates that hold the new flatbottom rail to the timber sleepers will not be a specific resilient type. There are currently no resilient fixings on timber sleepers in tube tunnels on the LU network, as these are used on the stiffer concrete sleepers.
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,
David Wells FOI Case Officer FOI Case Management Team General Counsel Transport for London
