Examination of Witnesses (Questions 13420
- 13439)
13420. MS LIEVEN: My Lords, in response
to the questions yesterday, I was going to read something out
which has been compiled by the team. Of course, if the Committee
want Mr Thornely-Taylor to go back into the witness box, then
we are quite happy to do that, he is here, but let me read out
the position as we understand it and see where we can get to.
13421. My Lords, the way that the construction
railway works is that, as the TBM advances, temporary tracks are
laid behind in the invert or bottom of the tunnel and the tunnel
construction trains run on this, and they comprise a locomotive
and rolling stock. It is likely that the trains will consist of
a locomotive and three flat-bed trucks to carry the concrete segments
and another flat-bed for miscellaneous materials, a grout container
car and a man-rider for the workforce, so that is the form of
the construction train.
13422. CHAIRMAN: Of course the spoil
is going out on the conveyor.
13423. MS LIEVEN: The spoil is going
out on the conveyor, so this is the trains bringing the materials
in to effectively support the TBM. The locomotives are likely
to be diesel-powered with hydrodynamic or hydrostatic transmissions,
and I am going to refer to the noise information below. I have
got material on the frequency, but I do not think that matters
too much at this stage. The normal working speed of the construction
trains is 15 kilometres per hour and, in working areas and at
switching crossings, the speed will be reduced to five kilometres
per hour. There will be a set of crossovers adjacent to the Westbourne
Park footbridge and others adjacent to the Westbourne Park worksite,
so one can see from that that we are talking about very low speeds
here.
13424. The construction noise assessment, which
was carried out for the Environmental Statement, shows that baseline
noise levels for Westbourne Park Villas at that time were assessed
as 64dB LAeq eight hours at night. Now, that was for the ES, so
it was some time ago. The predicted construction noise level during
the tunnelling phase, that is the 24-hour operational phase, from
the above is 56dB LAeq and that was assessed for 99 Westbourne
Park Villas. Therefore, the tunnel trains would have to be considerably
louder than the other plant operating to increase the predicted
noise level by a sufficient amount to cause a significant construction
noise effect, and the manufacturer's noise information obtained
indicates that that is very unlikely to be the case. A point to
emphasise here, and I can call Mr Thornely-Taylor to deal with
this if the Committee want to take it further, is that my instructions
from him are that the predominant noise source from this kind
of activity is the train being loaded. It is not the trains going
along the tracks, it is the train being loaded, so it makes very
little difference whether you have a battery-operated train, a
diesel-operated train or indeed, as Mr Thornely-Taylor put it
to me outside, a horse-drawn train because it is not the trains
going along that are making the material noise here. In addition,
consideration of the operation of the construction trains shows
that they will create noise for a much shorter proportion of time
than the other plant and equipment. It remains a possibility that
movements in the construction train may be audible to nearby residents
on some occasions, but that has to be considered in the context
of other construction activity and mainline train traffic.
13425. The other point for the Committee to
note in terms of the reality of what is happening here is that
mention was made by Mr Berryman of battery-operated trains, and
my instructions are such that such trains have been used overseas,
for instance, we think, on the mass transit system in Hong Kong,
but we are simply not sure at this stage whether it would be feasible
to use battery-operated trains here, even if it were justified,
because we have very long tunnel drives. Since we changed the
tunnelling strategy a couple of years ago, we now have these very
long tunnel drives, and my instructions are, to put it non-technically,
that we are just not sure whether the batteries would manage to
get the trains to the right place, and they might run out of—I
was going to say "steam"—while in the tunnel.
13426. There were issues such as that which
simply have not been determined, but the important point to understand,
away from the technicalities, is that the Promoter has made a
commitment to apply section 61 of the Control of Pollution Act
process to the construction sites and that requires that the nominated
undertaker demonstrate that best practicable means to control
noise have been utilised.
13427. In the context of the construction train
and the selection of either diesel or electric trains, the Promoter
will have to demonstrate that the train type selected is the best
practicable means to control noise. It is for that reason that
if circumstances demonstrate that a particular train type has
material advantages over another train type, that will be highly
material to deciding what is best practicable means. Therefore,
to specify at this time a particular type of locomotive could
be counter-productive to achieving the best practicable means,
because you might specify now battery-operated and you might find
that that was not best practicable means. So actually, it is not
in anybody's benefit to try to pin this issue down at this stage.
13428. The commitment to use best practicable
means in this regard means the Committee can be completely confident
that this issue of whether there is any material impact on noise
will be fully taken into account in the final decision as to what
type of train to use, as of course will be the reality of whether
we can get battery-operated trains to do the job in any event.
13429. I have given that really in order to
save time as we are on the last day, but if the Committee want
Mr Thornely-Taylor to give evidence or just to go into the witness
box—
13430. CHAIRMAN: Before we decide on
that, did I understand you to say that it is not the locomotive
that is going to be causing the noise; it is putting the segments
or whatever it is on to the presumably flat wagons?
13431. MS LIEVEN: The predominant noise
source is the train being loaded. I do not want you to think we
drop the segments and they go "crash!" because apparently
that is not what happens. Apparently, a major part is the crane
noise of bringing them over. It is the train being loaded; it
is not the actual noise from the locomotives. It is completely
different from the EWS issue at the batching plant, where the
noise source is the noise coming out of the top of the train.
We are talking about a very different scale of noise here.
13432. CHAIRMAN: You are putting material
on to the flat trucks with a crane.
13433. MS LIEVEN: Yes.
13434. CHAIRMAN: Presumably, it makes
a noise when they get on to the platform of the vehicle.
13435. MS LIEVEN: Yes, my Lord. I keep
being told it is the crane, not the material hitting the flatbed
truck.
13436. CHAIRMAN: It is the crane that
makes the noise.
13437. MS LIEVEN: It is the crane that
makes the noise.
13438. CHAIRMAN: So it is a diesel crane.
13439. LORD JAMES OF BLACKHEATH: It is
the chain in the crane that makes the noise.
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