Select Committee on the Crossrail Bill Minutes of Evidence


Examination of Witnesses (Questions 12340 - 12359)

  12340. BARONESS FOOKES: We already have the noise expert here in the room able and willing to give evidence. Surely that meets your point, Lady Bright?

  12341. LADY BRIGHT: Yes.

  12342. MS LIEVEN: I have no re-examination, my Lord Chairman.

  12343. CHAIRMAN: Mr Berryman, the turn-back facility is not going to add to the noise, is it? I know it is a bit further, as it were, to the left?

   (Mr Berryman) It will do in as far as trains come into the turn-back facility and then go out again. There will be a platform in the turn-back facility so there will be some shielding of the noise generated by the trains and of course they will be going very slowly because they are about to turn back, but yes, they will be part of the noise generated by Crossrail.

  12344. They presumably clatter across a set of points somewhere?

   (Mr Berryman) `Clatter' is perhaps not the word I would have used, my Lord, but they will pass across a set of points.

  12345. LORD JAMES OF BLACKHEATH: Is there any notable noise variation in the start-up of the engine when presumably they are going to start the engine?

   (Mr Berryman) No, my Lord, they are electric trains so it will be the familiar hum that you will have heard of motors on the existing railway will be what you get.

  12346. CHAIRMAN: Thank you very much, Mr Berryman.

  12347. MS LIEVEN: Thank you, Mr Berryman.

The witness withdrew

  12348. MS LIEVEN: Can I call Mr Thornely-Taylor.

MR RUPERT THORNELY-TAYLOR, recalled. Examined by MS LIEVEN

  12349. CHAIRMAN: I expect the sensible thing, Ms Lieven, is to get his evidence-in-chief and leave cross-examination until this afternoon.

  12350. MS LIEVEN: We should be able to complete the evidence-in-chief.

  12351. CHAIRMAN: Mr Thornely-Taylor can come back after lunch?

  12352. MS LIEVEN: Mr Thornely-Taylor is here for the duration! Mr Thornely-Taylor, you are well-known to the Committee and indeed to Lady Bright so I am not going to introduce you. Can we go straight to the heart of one of Lady Bright's concerns? Can you explain what noise studies have been already undertaken and what noise studies will be undertaken in the future and what matters they will take into account?

   (Mr Thornely-Taylor) The studies which have already been undertaken were those which were done primarily for the purpose of preparing the Environmental Statement. Those were necessary because the methodology of environmental assessment involves characterising the baseline environment before you assess the effect of the likely changes that result from the project in terms of the significant effects that will result. That has been done, as your Lordships know, but there are further stages which will be necessary for three main reasons. First of all, there is the matter of construction impact when the time comes to plan the works in detail. You have heard about the process of the section 61 consent procedure and that requires the preparation of detailed methods of working and quite often involves noise data, both measured and predicted, but alongside that is the question of testing for potential eligibility for noise insulation or, in some cases, temporary rehousing under the scheme, which is explained in Information Paper D9, and for that purpose a measured background noise survey is required because again the baseline noise environment plays a role in determining whether or not triggers for noise insulation or, if it arises, temporary re-housing are met. That is then put with the much more detailed construction noise predictions that become possible when the contractor is on board, the plant team is known in much more detail, the method of working and programme is known in much more detail, and eligibility from which will have triggered the flow of offers of noise insulation will be determined, but there is also the question of eligibility for statutory noise insulation according to the noise insulation regulations for railways, which is about operating railway noise. There are several important tests which have to be carried out according to the regulations. That is actually a theoretical process. It is done by calculating the railway noise that exists before you consider the contribution of the new railway and you then look at four tests, the absolute day and the absolute night noise level, the amount by which either of those noise levels will be increased as a result of the new railway, and also what is the contribution of the new railway to the overall noise environment, and from that can also flow an offer of noise insulation through the statutory scheme. Those are the main processes which will take place, they have to take place, both in satisfaction of the regulations and to carry out Crossrail's own policies and procedures set out in the information papers.

  12353. Just to be absolutely clear on two of the points Lady Bright has raised, will those processes involve taking into account the cumulative noise from different sources and the existing noise?

   (Mr Thornely-Taylor) The survey which is carried out for assessing the construction impact involves measuring the total noise at the location, from the railway, from Westway, from other roads, from aircraft, from anything which happens to be measured during the survey. The question of eligibility for noise insulation against the operating railway is uniquely about railway noise and does not take into account the contribution of other sources.

  12354. And then just staying on process for a moment, in terms of taking into account railway noise for the operational phase, will the fact that there is proposed to be a reversing facility near Westbourne Park be part of the railway noise which is taken into account?

   (Mr Thornely-Taylor) Yes, it is.

  12355. Okay then, let us move on to the existing situation. Can you just describe the noise climate at Westbourne Park Villas in the existing situation, please?

   (Mr Thornely-Taylor) Yes, on the north side of Westbourne Park Villas, as we have heard, there are high noise levels. It is a fairly intense transport corridor with not only several railway lines, several railway services, but the highway system up on the viaduct at Westway. It is probably one of the areas of London among the highest levels of railway noise, though, as we have heard, significantly reduced just in recent months. The last of the engine upgrades that took place for the Intercity 125 trains was completed just in February 2008 so it is a very recent improvement in the noise climate but, nevertheless, because of the presence of the Great Western Main Line the suburban lines, and the London Underground lines, there is a large amount of railway noise at present and indeed has been there since the time of Brunel. Westway, as we have heard, also carries large traffic flows and contributes a significant amount of traffic noise and there are of course local roads as well.

  12356. In terms of taking in account those recent changes to the noise environment, will they be taken into account in the process that you described before for calculating mitigation for both construction and operational conditions ?

   (Mr Thornely-Taylor) Yes, they will be fully taken into account.

  12357. Just give us some sense as to what relevance they may have for statutory noise insulation?

   (Mr Thornely-Taylor) The most interesting consequence of railway noise having improved in recent times as a result of the engine upgrades we have heard about is that potential eligibility for statutory noise insulation from the operating railway arising from the Crossrail scheme is actually slightly greater because although Crossrail remains a minor contributor to the total noise environment, there is a very fine trigger required in the regulations which is that Crossrail should contribute 1dB to the total rail noise environment and the total noise environment should go up by 1dB. It is now looking as if that will now be much more clearly established for a larger number of dwellings along the Westbourne Park Villas frontage than was foreseen at the time of the last estimate which was in the last additional provision in the Environmental Statement. It is quite a large number that may be eligible using the current rail services as the baseline. As we have heard, there is another change coming. What is sometimes referred to as HST2, High Speed Train 2, will eventually completely replace the existing upgraded high speed trains with yet another change that we can only speculate about, but it does seem likely that the facades of these Petitioners may well become eligible when the time comes to calculate it for statutory noise insulation.

  12358. Just explain to the Committee, I think we have done so already but just remind us, what does statutory noise insulation mean in practice?

   (Mr Thornely-Taylor) It is defined in the regulations to which I have referred. It is the installation of a second window behind the existing window, often called secondary glazing, and the provision of alternative ventilation arrangements so that the windows can remain closed and a number of secondary matters such as the insertion of blinds between the panes (probably is not necessary in the north facing windows but in some circumstances it is) and it is all set out in the statutory provisions.

  12359. Moving on then to the residents' desire to have a noise barrier and that being preferable to having noise insulation; can you just explain what in noise terms as opposed to engineering terms are the issues around having a noise barrier at this location?

   (Mr Thornely-Taylor) A noise barrier works by interrupting the path from the noise source to the receiver of the noise, namely the windows of the house, and it has almost zero effect until the height of the barrier is great enough at least to reach the line of sight from the noise source to the window. The noise source, as we have heard, in the case of electric multiple units is done at the wheel-rail interface but in the case of diesels it is quite high up, it is taken formally as four metres above rail level, and therefore you do geometrical sections to show at what height a noise barrier has to be to ensure that the top of it reaches the line of sight from a sufficient number of noise sources to make a worthwhile difference. For a noise barrier to be effective in this location, it would need to protect against noise from all the different tracks, some of which are quite distant from the wall we have been looking at, and even in those cases if you do have a wall high enough to cut across the line of sight, because the distance is so great the defraction that occurs in propagation of noise from the source to the receiver becomes quite large and atmospheric effects, wind and wind turbulence, greatly reduce the effect of the barrier, so we can only ever look at a partial solution even it were a matter for Crossrail to consider reducing the noise from all the other railways. If we do strictly limit ourselves to considering what effect a barrier would have on Crossrail's contribution, which is the formal position, it can never, however high it is, reduce noise levels more than about one or two decibels below the case with no noise barrier at all because that is the order of magnitude of Crossrail's contribution in the future.



 
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