Select Committee on the Crossrail Bill Minutes of Evidence


Examination of Witnesses (Questions 12320 - 12339)

  12320. Listening to Lady Bright's questioning, the area we have not discussed is actually the quality of the material and the thickening of it as opposed to just scaling the sound out with height.

   (Mr Berryman) It is really the strength of the mortar which is the crucial thing. The bricks themselves have a bearing on it but the mortar is the crucial thing. We have taken the mid-range from BS5628, which is probably a slightly optimistic assumption because this is pretty old mortar; it has been there the thick end of a hundred years.

  12321. The mortar would not be a factor if you faced both sides of it with bolted-on, or some other way, fixed plates of very sound-resistant material.

   (Mr Berryman) My Lord, that would not help because when the wall fails it will fail as a piece; it will not sort of bend in the middle, it will just fall over at the point of highest stress, which is at the bottom of the wall. That is where the tensile stresses—

  12322. A plate on both sides would not provide a compensating stress.

   (Mr Berryman) Not really, no. You could do it in one direction but not the other.

  12323. I could not even manage my Meccano set so I should not be asking any questions, but I am fascinated by the fact that we seem to have had a relatively narrow discussion on what is a very important point. I am trying to broaden it into something I might be able to understand. I am surprised that Lady Bright has not been pursuing you on something similar with better knowledge.

   (Mr Berryman) My Lord, if you were to put what we call "flats"—steel flats—down on, say, this side of the wall, it would stop the wall falling over towards Westbourne Terrace, but it would not help you with the wall falling over into the railway.

  12324. I would be thinking of something more like a very large acoustic tile.

   (Mr Berryman) I am not aware of anything which can strengthen a masonry wall in that way, my Lord. As I was saying earlier, there has been some experimental work done on strengthening concrete walls by bonding carbon reinforced plastic to the face of the wall, but that is really at an experimental stage at the moment.

  12325. The thrust of my question is, as it is on so many of these occasions with us here, that we get the question and we get the answer but what always fascinates me is the answer to the question that has not been asked. That is all I am trying to probe for.

   (Mr Berryman) Indeed, my Lord. I cannot really help you there, I am afraid. It sounds like a Zen question, if I may say so.

  12326. LADY BRIGHT: Just to finish on this height business, what height barrier could that wall sustain?

   (Mr Berryman) As Lord Brooke asked that question earlier on, without extra calculation I could not tell you but it would not be very high.

  12327. Everything you are telling us is ruling that out and we have not got engineering data to respond to how you might deal with the barrier on that location and done in that way. We did not come here to specify exactly how the noise barrier should be made, because we still do not have the noise data to know precisely what problem we are supposed to be solving. It must go back to that. Is that not correct, Mr Berryman?

   (Mr Berryman) As I said, Mr Thornely-Taylor is better qualified than I to answer that question, but I think what their Lordships are already aware of, as a result of the site visit, is that the noise in that area has recently significantly reduced because new trains have been put in. The point is background noise levels change over time, and if we had done this work a few months ago the background noise level in your property would have been extremely high (I think you would agree with that) and it is now somewhat lower. I am not saying it is low but it is lower than it was. So, the timing of when noise measurements are made is relevant to the level which will be experienced.

  12328. Would you agree, Mr Berryman, there are other changes in the pipeline—you have mentioned this—further down the years before the trains start running which will affect the noise environment again and reduce the noise, probably?

   (Mr Berryman) They may do. It is very hard to say for sure what impact some of these things will have in the future. You are probably aware of the so-called Intercity Express project which is planning to bring new Intercity Trains onto the network. They are out to tender, I think, at the moment, but we do not know yet what the noise level will be from that.

  12329. Is it true they may be electric, do you think?

   (Mr Berryman) It is possible. Technical opinion is divided on that matter, at the moment.

  12330. You probably know as well as anyone when we might know about that.

   (Mr Berryman) I would not like to hazard a guess about another person's project. I do know that they are in active discussion with manufacturers at the moment, and the result of those discussions will no doubt lead to a decision on electrification or otherwise.

  12331. Could I ask you what you know about this detailed noise study that your colleagues have been promising us?

   (Mr Berryman) I think the best person to ask that is Mr Thornely-Taylor.

  12332. I concede you say that but I thought you would know if there was another set of studies to be done because it would affect the way you approach this end of the track.

   (Mr Berryman) It could be done, yes. There will certainly be other studies to be done between now and when the railway opens.

  12333. So you are not clear about the scope of the study that Crossrail is proposing to do, because it does affect the noise barrier—what this study is looking at. The detailed noise study that I keep banging on about.

   (Mr Berryman) The detailed noise study will really be to do with measuring background noise and forecasting what future noise levels will be and what remedial action, if any, needs to be taken. As I keep saying, Mr Thornely-Taylor is far better qualified than I to answer that question.

  12334. I must press you on this: do you understand it to be taking account of the cumulative effect of the different noise sources? Do you understand the study we are talking about to be a very sophisticated modelling exercise so that it can account for the change if the Government goes for electric or diesel/electric units—the change when the new noise laws bite on the Westway, etc. Is that your understanding, or are you thinking of a much more limited study?

   (Mr Berryman) Again, I am not really the best person to answer that question. The study that is to be done will be done in accordance with the various regulations and such that govern these matters. I am sure Mr Thornely-Taylor will be delighted to answer these questions.

  12335. LADY BRIGHT: You are the managing director—

  12336. MS LIEVEN: My Lords, I hesitate to rise. I have the noise expert sitting behind me and I intend to call him as soon as Mr Berryman is not in the box. Mr Berryman has said he is not the right person to answer these questions.

  12337. CHAIRMAN: He is saying so, loud and clear.

  12338. LADY BRIGHT: He is saying that he does not know about the technicalities, but it is a major item that would affect their work on this. If it is what we think is meant by it. So I just wanted to establish what Mr Berryman—

   (Mr Berryman) If I could just make the point, Lady Bright, that Crossrail is a very large organisation which involves all kinds of different specialists who deal in all sorts of different matters. Although I have a general understanding of what they are all doing I do not think I could put myself in their shoes and take some of the specialist decisions which are taken.

  12339. That is probably our point to some extent: what matters a great deal to us does not matter a damn to anyone else.

   (Mr Berryman) I do not think that is what I said.



 
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