Examination of Witnesses (Questions 19920
- 19939)
19920. The speed of the trains under the sensitive
area, I gather that they reduce from 20kph to 5kph, is that right?
(Mr Berryman) That is right.
That is the idea, yes.
19921. Reducing them, say, to 3kph, I am just
picking that as a figure, on the assumption that it reduces noise
impact as a result of doing that, why do you say that is impossible
in terms of the construction of the railway?
(Mr Berryman) Just by virtue
of the journey time that would be involved. You have got to bear
in mind that we are talking about a single track railway here
which has to solve the tunnel boring as it is going on, so a train
cannot come out until another train has gone in, so the longer
you increase the journey time the more difficult it is to keep
servicing the machine as needed. Of course, it is not just your
client's premises where there are sensitive issues; there are
a number of other premises in the same area where we will also
be meeting these noise criteria.
19922. I understand that obviously but what
is the extra time factor of travelling the 110 metres or so at
3kph as opposed to five? What is the time penalty?
(Mr Berryman) I cannot tell
you offhand. It will be a few minutes by the time the train has
slowed down, gone at this crawling speed and then speeded up again.
19923. That sounds quite a lot, if I may say
so, a few minutes to travel 100 metres, the difference between
the 5kph and 3kph.
(Mr Berryman) If it was
100 metres it would not be very long but it will be more than
10 metres because the length of the train itself has got to be
part of that. The front of the train gets to a certain point,
you pass under the length at restricted speed and you cannot speed
up until the back of the train has passed it. Moreover, I do not
think there is any fundamental difference between your client's
property and the other sound sensitive sites in the area.
19924. There may well be but that in itself
is not of assistance. What I want to know is, is there a spreadsheet
or some calculation that we can look at to justify the assertion
that it is several minutes?
(Mr Berryman) No, there
is not. You would have to calculate that. Frankly, 5kph is a slow
walking speed. We have never given serious consideration to operating
trains at a lower speed than that.
19925. Why?
(Mr Berryman) The benefits
are just not commensurate with the inconvenience.
19926. What is the financial penalty that is
concerning you? It can clearly be done in practical terms.
(Mr Berryman) It is not
so much a financial penalty, it is just the operation of the whole
system, the railway, the tunnel boring machines, everything working
together. I suppose it is possible to go more slowly but are the
benefits really worth it?
19927. That is a separate question. You know
that our case is if you reduce the speed you do get considerable
benefits.
(Mr Berryman) I think if
you reduce the speed from 20kph to 5kph you obviously do get significant
benefits but you get to the law of diminishing returns and if
you go slower and slower, the benefit you get is less and less.
19928. Benefit to whom?
(Mr Berryman) Benefit in
terms of noise reduction.
19929. I do not think that is your area, is
it?
(Mr Berryman) No, it is
not, but I do happen to know that is the case.
19930. What was your research to come to that
conclusion?
(Mr Berryman) Experience
of how these things work in practice.
19931. What does your experience tell you, please,
on the reduction from 5kph to 3kph in terms of noise?
(Mr Berryman) I do not have
specific experience of reducing from 5kph to 3kph but I do have
general experience of the impact of speed on noise.
19932. I will not press you any more on that.
Are you the right person to ask about different types of rail
once the initial rail goes in?
(Mr Berryman) Yes.
19933. If the tunnel boring machine has gone
under Grand Central Studios behind there is a particular form
of track, is there not?
(Mr Berryman) Yes.
19934. Later on I think someone comes along
and alters that type of track from six metre to 15 metre lengths.
(Mr Berryman) Yes, by welding
the joints, that is correct, either welding the joints or replacing
the lengths. There are several ways to do it.
19935. What are the contingencies? If there
was a structural failure of the rail that had been laid, either
in terms of the rail itself or its support or its foundations,
what would you do?
(Mr Berryman) We would either
replace the length of rail or weld it depending on the nature
of the problem.
19936. What about if the foundations that the
rail was standing on, the clips or the concrete bedding, whatever
it is it is resting on, what happens if that fails for some reason?
(Mr Berryman) It would be
extremely unusual for that to fail. The rail will be laid, as
Mr Thornely-Taylor described, on top of ballast which should be
laid itself on top of the rubber mat in the invert of the tunnel,
so it will be resting directly on the concrete under the lower
part of the tunnel.
19937. I understand it might be unlikely but
what would happen?
(Mr Berryman) If that happens
you would bring some more ballast in and tamp it by hand to make
the ballast good. It is a very well established technique in railway
construction.
19938. Presumably in the schedules and the way
you look at it, you do contemplate things going wrong when you
are drawing up these schedules?
(Mr Berryman) Yes, there
is always a contingency in the timeframes.
19939. Why would it not be possible after the
initial rail has been laid thereafter to have a run of continuous
welded rail, not at the same time as the tunnel boring machine
is going through but retrospectively after that? Why is that not
possible?
(Mr Berryman) What you will
get is a rail welded into longer lengths than six metres, you
would get—
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