Select Committee on the Crossrail Bill First Special Report


Statement from the London Borough of Camden (paragraphs 7726-7750 in the transcript)

The London Borough of Camden is the lead authority on the issue of groundborne noise from the operation of Crossrail trains in tunnels, supported on this matter by Westminster City Council, London Borough of Islington, City of London and London Borough of Tower Hamlets. I am sure that the Committee is now very familiar with what the groundborne noise is. It can be described as the rumbling sound that is heard inside buildings during the passage of trains in tunnels.

The basic point of dispute between the collective local authorities and the Promoter is a simple difference in the numerical standard that is to be applied in the case of residential dwellings affected by groundborne noise. The Promoter is relying on a design standard which permits levels of up to 40dBLAmax,S whereas the local authorities are looking for a standard not to exceed 35dBLAmax,S. The issue was brought forward by London Borough of Camden in the Commons Select Committee proceedings and the ongoing discussions have resulted in agreement of the wording of an Information Paper. However, this basic point of difference has always been, and remains, a point of dispute between the parties. So I now need to explain to the Committee how this remaining and key point of dispute can have led to any kind of agreement whatsoever.

The Information Paper of interest to this matter is D10, and its scope covers groundborne noise and vibration during both construction and operation of the railway. London Borough of Camden's primary concern relates to the standard that has been adopted for the permanent railway, although many of the points that have been discussed also apply to the operation of the temporary construction railway that will service the tunnels during their construction.

Three of the local authorities affected by the scheme have specific policies on train groundborne noise inside dwellings, whilst others apply relevant planning conditions on groundborne noise, and all are consistent in that they are set at a maximum level of 35dBLAmax,S in each case. There are no UK standards which relate to acceptable levels of groundborne noise within dwellings, although design standards and guidance published outside of the United Kingdom only supports the local authorities' position that 35dBLAmax,S is a more appropriate design aim.

We say that the Promoter's position is based largely on precedent, with the 40dBLAmax,S policy devised and supported through formal proceedings by Mr Thornely-Taylor on behalf of the Promoters of schemes including DLR, Thameslink, JLE and CTRL. During the presentation of evidence to the House of Commons Select Committee on this generic issue, London Borough of Camden sought to guide the Committee through the history of the adoption of 40dBLAmax,S as a design standard and to demonstrate that in its opinion the scientific evidence to support its application was poor, speculative and inconclusive, and that for those reasons alone a more precautionary approach was justified. Mr Thornely-Taylor has explained during these proceedings that in the case of JLE and the London section of the CTRL there have been no complaints to his knowledge, but more importantly that actual noise levels are much lower than the design standard of 40dBLAmax,S. These relatively recent flagship projects do not therefore shed any light at all on whether 40dBLAmax,S is an acceptable level because they evidently do not generate noise levels as high as this.

On the basis of evidence put before the House of Commons Select Committee by Petitioners on the need for more stringent groundborne noise commitments the Promoter was instructed to provide floating slab track or a similar technology at certain locations along the route. This has resulted in the Promoter reporting to London Borough of Camden in its letter dated 21 December 2007 that no residential properties along the tunnelled sections of the route are predicted to experience groundborne noise levels at or above 35dBLAmax,S at any location with the caveat that the final track specification will not be determined until the design of the tunnels is complete and their precise position fixed. We have heard during these proceedings that possible permitted changes to the tunnel alignment that could still occur would, in the majority of cases, lead to less than a single decibel of difference. On the face of it, therefore, the main objective of the collective local authorities appears to have been indirectly met.

The Promoter does not alter its design aim as presented in Table 1 of IP D10—and that is the third version, for information—to reflect this, even though it would not appear to impose any direct costs for it to do so.

Camden remains concerned that the 40dBLAmax,S standard does not withstand scientific scrutiny, but in the interests of achieving an acceptable outcome for the affected residents, and recognising the risk of attempting to force changes to what appears to be an immovable policy for reasons unknown by further representation in front of your Lordships, London Borough of Camden has sought to secure its objectives by other means.

The design aim criteria are of course based upon predicted noise levels, and there was debate in the other House about how the actual noise levels when the railway is operational (the so-called "outturn" noise levels) will relate to those predicted values, and what comfort any of the Petitioners and other affected parties can take away from these proceedings that they will actually be realised.

However, the Promoter has rejected our request to demonstrate compliance with its design aims by measuring noise levels once the railway becomes operational.

So that is the background to the agreed approach.

Our agreement to IP D10 version 3 is therefore based on securing wording which can be summarised as follows. The prediction model which is to be used for the detailed design of the track system will conform to best practice and be in accordance with the relevant International Standard on groundborne noise prediction issued in 2005, showing full compliance with its guidance on development, calibration, validation and verification. That recites D10 paragraphs 4.1 and 5.1.

That evidence of the model's accuracy is provided to the local authorities for their comment—D10 paragraph 5.1.

That the nominated undertaker will engage in continued technical discussions relating to track design and will take into account the local authorities' comments—D10 paragraph 4.2.

That the rails of the new railway will be ground smooth prior to the opening of the railway—D10-2.11.

That the gradual deterioration in rail and wheel condition will be limited to control any consequent worsening of groundborne noise and vibration—D10 paragraphs 2.10 and 2.11.

That the key input assumption of the combined condition (or "roughness") of the wheels and rails will not exceed that which has been, and will continue to be, assumed in the modelling, by way of imposing a specification on the operator of the railway—D10, 2.10.

To include recognition that the local authorities apply different policies to those proposed by the Promoter—D10, 2.13.

That the nominated undertaker will use "reasonable endeavours" to adopt mitigation measures that will further reduce any adverse environmental impacts caused by Crossrail insofar as these mitigation measures do not add unreasonable costs to the project or unreasonable delays to the construction programme—D10, 2.14.

On completion of the track design, where the nominated undertaker predicts that it would exceed the local authorities' preferred standard of 35dBLAmax,S at any dwelling, then the nominated undertaker will provide additional information to the local authorities explaining its position, and will take into account the local authorities' comments—D10, 2.13 and 4.2.

The definition of an adverse groundborne noise impact is specific in the context of this project. According to the Promoter's assessment criteria an adverse impact will not occur if the groundborne noise levels are below 35dBLAmax,S. The Promoter has declared that following the incorporation of the additional mitigation as instructed by the House of Commons Select Committee, there are no adverse groundborne noise impacts expected at residential dwellings across the tunnelled section of the route.

The contents of the Environmental Minimum Requirements: General Principles paper, which have been agreed by the Promoter and the Local Planning Authorities, has assisted us greatly in achieving agreement to IP D10 Version 3. The relevant passage from the EMRs General Principles paper can be found at paragraph 1.5 and requires the nominated undertaker to use reasonable endeavours to adopt mitigation measures that will further reduce any adverse environmental impacts caused by Crossrail, insofar as these mitigation measures do not add unreasonable costs to the project or unreasonable delays to the construction programme.

Of note is that the commitment in paragraph 1.5 stands "apart" from the controls and obligations in the EMRs that specifically require that impacts which have been assessed in the 2005 Environmental Statement will not be exceeded. In our view the provisions of paragraph 1.5 should be seen in the context of the most recent predictions undertaken by the Promoter (i.e. post-Environmental Statement), the results of which conclude the existence of no adverse impacts. By this the Petitioners seek to put on public record that with no adverse impacts currently envisaged by the Promoter the local authorities are expecting that the application of reasonable endeavours would ensure that groundborne noise levels inside dwellings fall below 35dBLAmax,S.

This series of commitments and observations has enabled agreement on the principles of IP D10 Version 3, but as explained previously not to the maximum permissible limit for residential dwellings which remains presented in Table 1 of that document, and which the Promoter does not alter despite no cost burden apparent to the project in doing so. This is a fundamental point for local authorities to put on record as it should not be regarded as any precedent for future railway schemes or other development where groundborne noise is a concern and where local authority policies need to remain intact to prevent challenge to their saved policies on groundborne noise.

I hope that your Lordships can appreciate the major obstacles around which Camden has had to negotiate in reaching an agreement on this matter.

Statement by the Promoter in response to the Statement by the London Borough of Camden

We had understood that an agreed position in relation to groundborne noise and vibration had been reached with the London Borough of Camden and it was not until yesterday that we found that Camden would be continuing to make points to you this morning regarding the appropriateness of 35dBLAmax,S as a design noise criteria, and it is only right that I make clear the Promoter's position in relation to that issue.

This statement is to make it clear for the record that the Promoter continues to consider that a design noise criterion of 40dBLAmax,S affords an appropriate level of protection to the amenity within residential properties from noise from underground railways. Nothing in Information Paper D10 should be taken as indicating that the Promoter has changed its position in relation to that matter. IPD10 retains 40dBLAmax,S as the design noise criterion for the protection of residential properties in the design of the Crossrail project. The Promoter relies upon the fact that 40dBLAmax,S has been successfully used in the past as a design noise criterion in relation to a large number of underground railway schemes, including, for example, the Jubilee Line Extension. The Promoter is not aware of any complaints regarding groundborne noise associated with the Jubilee Line Extension from those occupying residential properties above it. The use, therefore, of 40dB as a design criterion has in fact protected the amenity of residential occupiers in that particular case.

The Promoter believes that the use of a 40dBLAmax,S criterion corresponds to a level of noise that is lower than the relevant thresholds in the guidelines for community noise published by the WHO. The Promoter does not believe that there is any published scientific evidence to suggest that the adoption of a 35dBLAmax,S criterion would produce any material improvement to the amenity of residential occupiers compared to the adoption of a 40dBLAmax,S criterion, and that is a point that was accepted by Mr Methold, who is the noise expert for the London Borough of Camden, in cross-examination before the House of Commons Select Committee, and you can see that in volume 2 of the Special Report at page Ev302, paragraph 3061. The adoption of a design criterion of 35dBLAmax,S would, therefore, potentially impose additional cost on an underground railway project whilst not bringing about any material benefit to the living conditions of those living above it. In short, the Promoter considers that 40dBLAmax,S provides a design noise criterion that works and a design noise criterion that is cost-effective.

Notwithstanding this continuing disagreement between the Promoter and the London Borough of Camden regarding the appropriate design noise criterion to adopt, the content of IPD10 is now agreed and, given that, there is no need for the Committee to resolve the issue between the parties. If, however, the Committee feels that it has to resolve that issue, we would ask the Committee to decide now whether it wants to take that course because, if it does, the Promoter will wish to call further evidence from Mr Thornely-Taylor to assist you in your deliberations, so we would ask you please, if you would be kind enough, to decide now whether you wish to determine the issue about 35dB or 40dB, and we say you do not need to, but, if you do, we will call evidence before you.

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