Examination of Witnesses (Questions 3000
- 3019)
3000. The next undertaking I want to have a
quick look at is your fifth one, LBC38, which seeks, as I understand,
information on the frequency of routine maintenance regimes. The
criteria under which maintenance activities such as wheel turning
and rail grinding will be triggered. You seek to impose the best
practicable means on the maintenance regimes, if I might put it
colloquially. In that regard, can I again draw the Committee's
and your attention, Mr Methold, to information paper D10, page
3? This time paragraph 2.10. Here we see that: "The nominated
undertaker will put in place measures that will ensure that the
track of the underground sections of the wheels and vehicles operating
the Crossrail passenger service are maintained in a state which
under all reasonably foreseeable circumstances will lead to adequate
control of groundborne noise and vibration arising from the railway.
Prior to opening, the nominated undertaker will ensure that the
rails of the underground sections of Crossrail are conditioned
by grinding, or other suitable means, and are appropriately maintained
thereafter" Your concerns, I would suggest, are met by paragraph
2.10 of information paper D10.
(Mr Methold) The local authorities
are intrigued by the wording "adequate control of groundborne
noise and vibration". We do not believe this is very committal
and we want to understand more and attach the best practicable
means attachment to that undertaking.
3001. I see. Let us go to the nub of the issues
between us. That arises out of the undertaking that you seek as
undertaking 4 on LBC38. I just want to take a moment to look at
the wording of the undertaking sought at number four. You are
seeking this: "The nominated undertaker will apply best practicable
means to the design of the temporary construction railway and
the permanent operational railway." That is the first point
to note, the best practicable means applied to the design of both
of those railways, "such that the groundborne noise level
from a single train pass-by measured close to the centre of any
habitable room within a building legitimately occupied for residential
purposes, does not exceed a level of 35 dB LAmaxS". So you
are also seeking to apply to the design of both railways a level
of 35 dB LAmax.
(Mr Methold) Correct, yes.
3002. So your proposed undertaking, as I understand
it, is inevitably based upon modelling not upon measurement, because
the criterion is to be applied at the design stage.
(Mr Methold) I do not believe
that was the intention of that wording.
3003. It is not the intention of the wording?
(Mr Methold) No. I think
we intended to cover for the non-predicted situation.
3004. So you are intending that the noise level
of 35 should apply after the railway has been built.
(Mr Methold) That is correct.
3005. So you go into a room and measure the
noise, and it has to be below 35.
(Mr Methold) Correct.
3006. I have to say, I had understood that your
evidence to the Committee was that once a railway had been built
you could not change it so as to provide additional protection.
(Mr Methold) Indeed.
3007. So can you just explain what is the point
of having an undertaking that relates to a 35 dB(A) measured level
if there is actually nothing you can do if the design does not
meet the 35 level to begin with?
(Mr Methold) It is a test
to ensure that best practicable means are being employed and this
is to cover the maintenance aspect also. So if we have a situation
where the design is not 35 but if somebody measures above 35 then
that might indicate that the maintenance of the railway does not
meet the requirement of best practicable means.
3008. Let me take a step back from that. The
issue that we have is the level at which to set the threshold
and also whether or not best practicable means should apply. So
far as the threshold level is concerned, what we are concerned
to do is to set that threshold at a level that is appropriate
to expect people to live with. Do you accept that?
(Mr Methold) Yes.
3009. In terms of identifying what that level
should be, we need to have regard to dose response research.
(Mr Methold) Yes, we do.
3010. As I understand it, your case is that
35 dB LAmax is the level it is appropriate to expect people to
live with and no higher.
(Mr Methold) Yes.
3011. So noise below that level is acceptable.
(Mr Methold) It would be
audible but it is acceptable.
3012. If we also apply best practicable means,
the application of best practicable means has the potential to
require measures to be taken that would result in noise being
reduced to a level significantly below 35.
(Mr Methold) Potentially,
yes.
3013. So the application of best practicable
means has the potential to impose costs in the form of mitigation
that would need to be provided that would not give rise to any
material benefit to the noise environment people would have to
live with.
(Mr Methold) Part of "best
practicable means" is consideration of financial implication,
and all these aspects would have to be weighed up if there was
a significant cost associated with reducing noise levels well
below 35—
3014. Let us look at it this way and see if
we can explore it in this way: if the noise level of 35 is acceptable
then there would be no purpose in requiring any additional mitigation
on your basis because the noise is already at an acceptable point
and any additional cost would not be best practicable means.
(Mr Methold) I think Mr
Thornley-Taylor 's modelling would suggest it could be achieved
to go lower than 35.
3015. Just to answer my point, Mr Methold, if
you would be so kind, the point is simple: that if 35 is acceptable
then any further mitigation would not be required on the application
of best practicable means.
(Mr Methold) If 35 is deemed
to be acceptable. Additional costs to go below 35—
3016. So if the criterion is set at a level
that requires 35 to be attained, there is no additional benefit
in requiring an undertaking that refers to best practicable means.
(Mr Methold) Best practicable
means can work the opposite way; it would allow the Promoter to
argue in situations where it could not achieve 35.
3017. I see. So where you refer to best practicable
means, what you are intending is that it should bite in situations
where 35 cannot be achieved.
(Mr Methold) I think that
is fair, yes.
3018. Again, forgive me, but I thought the thrust
of your evidence to the Committee was that 35 could be achieved
for the whole length of the route.
(Mr Methold) Well, I did
couch my evidence very carefully by saying that it was based upon
information I had been provided with; it was based upon looking
through the information in the few days I have had available to
do that. It also is not clear to me whether some of the special
buildings that had been considered were residential or commercial,
but to err on the side of caution I did assume them all to be
residential. On that basis I felt that 35 could be achieved.
3019. Again, just looking at 35 for a moment
and using that, I think you would accept that at that level the
noise will be audible but, you say, acceptable. Is that right?
(Mr Methold) It is the division
line between barely perceptible and distinctly perceptible. So
I would argue that it is audible but acceptable.
| 
