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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