A very noisy bird, part 1

If my memory serves me correctly – and after around one hundred days of petition hearings my powers of recollection are not at their best – the expert testimony presented to the HS2 Select Committee on noise has, with one recent exception, been entirely from the Promoter’s side. That exception came in July this year when Halton Parish Council, Wendover Parish Council, The Wendover Society and Wendover HS2 jointly put up Steve Summers, a Member of the Institute of Acoustics and Associate Director of ACCON UK Environmental Consultants, as one of their witnesses (see footnote 1).

On the rare occasions when Rupert Thornely-Taylor has given evidence on behalf of the Promoter, he has, when faced only with non-expert petitioners, been able to assume the role of fount of all knowledge and play the friendly uncle to us poor schmucks who have dared to challenge the line we are being fed on noise, whilst failing to disguise his utter contempt for our obvious ignorance. As can be seen from his biography, Mr Summers is well able to trade CVs with Mr Thornely-Taylor, and the sight of the latter taking on someone his own size, so to speak, would have been an event to relish. Unfortunately, we were denied that pleasure. Tim Mould QC, Lead Counsel for the Promoter, appears to fancy himself as competent on matters acoustic and rebuffed the petitioners’ case himself, not calling Mr Thornely-Taylor to give evidence. In the process, I feel that he was guilty of a discourtesy to Mr Summers, an unfortunate impoliteness that was further exacerbated by insufficient time being allocated for his testimony due to “mixed messages” regarding timetabling (see footnote 2).

What we were able to hear from Mr Summers served to vindicate the complaints that have been made by a number of petitioners that HS2 Ltd’s preference for quoting noise as equivalent continuous sound levels tends to understate the impacts. His evidence was routed firmly in noise expressed as the maximum levels from train pass-bys (LpAFmax), and two exhibits that he employed clearly illustrated why this was his preference.

The first of these exhibits, A1212(11), reproduces one of the noise maps prepared by HS2 Ltd for Volume 5 of the Environmental Statement (ES). The exhibit shows the section of the proposed route of HS2 passing Wendover and the extent of the penetration of predicted HS2 operational noise that is above the lowest observed adverse effect level (LOAEL) into the town; locations predicted to experience levels above LOAEL are indicated by the shaded areas. In common with all such noise maps in the ES, the map employs the equivalent continuous sound level, LpAeq,T. LOAEL is taken to be 50 dB LpAeq,07:00-23:00 during the day and 40 dB LpAeq,23:00-07:00 at night; locations at LOAEL by day and night are assumed to be coincident. Mr Summers pointed out to the Committee that “the majority of Wendover town is outside of [the area where LOAEL is exceeded]” (see footnote 3).

However, subsequent to the ES being published HS2 Ltd issued Information Paper E20, which sets an alternative value for LOAEL at night of 60 dB LpAFmax (see footnote 4). Despite introducing this additional way of expressing LOAEL that employs the maximum train pass-by noise level, HS2 Ltd has made it clear that it does not plan to issue maps showing the maximum level, despite the opportunity that was afforded by the need for the Supplementary ES.

A glance at Mr Summers’ second exhibit, A1212(12), should explain this reluctance. On this exhibit Mr Summers has plotted the 60 dB LpAFmax contour in green, indicating the penetration of LOAEL night into Wendover using this alternative peak measure. This new map shows, in Mr Summers’ words, that “a large part of the town is above the lowest adverse effect level” – certainly much more of the town than if the equivalent continuous sound level is used to determine LOAEL and, as Mr Summers pointed out, up to 36 train movements an hour were possible on the line. From this part of his evidence it does look as though many Wendover residents can expect significant sleep disturbance due to HS2.

This apparent disparity between the maps for LOAEL drawn using LpAeq,T and LpAFmax has been brought to the attention of the Select Committee before; in December last year Cllr Andrew Burrow, a witness for the Berkswell Society, presented his exhibit A556(47) to the Committee. The exhibit is a map showing the areas of Berkswell that HS2 Ltd has predicted will experience peak noise in excess of 60 dB LpAFmax compared with the LOAEL night contour of 40 dB LpAeq,23:00-07:00. Cllr Burrow told the Committee how he had constructed this map (see footnote 5):

“… I took an HS2 map, which is this one, and I circled every noise-monitoring point – sorry, prediction point where the predicted noise was above the 60dB, but I ignored the TS1-compliant trains – i.e. the noisier trains – because I assume, with the abolition of the Channel Tunnel link, these will not occur, so I’ve just taken the noise-efficient new trains that HS2 are projecting”.

The conclusion resulting from this exercise that he presented to the Committee was:

“… you get quite a lot of red spots all over the place, and they’re outside, you will notice, the 40dB night limit, which is the grey shaded area, and a lot of them go deep into the Riddings Hill Estate.”

(To be continued …)


  1. Mr Summers’ evidence was given during the public session held by the HS2 Select Committee on the afternoon of Tuesday 14thJuly 2015. The relevant passage is recorded from paragraph 165 of the transcript and may be viewed from 14:49 hrs in the video of the session.
  2. For an explanation why time constraints were imposed, but not of the circumstances that led to the debacle, see paragraphs 2 and 3 of the transcript of the afternoon session of the HS2 Select Committee held on Tuesday 14thJuly 2015.
  3. See paragraph 176 in the transcript of the afternoon session of the HS2 Select Committee held on Tuesday 14th July 2015.
  4. Refer to Table 1 in Appendix B of Information Paper E20 Control of Airborne Noise from Altered Roads and the Operational Railway.
  5. Both of Cllr Burrow’s quotes are recorded in paragraph 120 of the transcript of the morning session of the HS2 Select Committee held on Wednesday 10thDecember 2014.

PS: If you are puzzled by the title of this blog series, seeing no connection between the above and ornithology, you will have to wait until part 2, when I promise that the creature in question will make an appearance.

Important Note: The record of the proceedings of the HS2 Select Committee from which the quotes reproduced in this blog are taken include an uncorrected transcript of evidence, which is not yet an approved formal record. Neither witnesses nor Members have had the opportunity to correct the record in such instances, and it may therefore be subject to changes being made in the light of any such corrections being requested.


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