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The
following has been prepared on a collaborative
basis with contributions from several
people including employees of London Underground.
Will
a Turnham Green stop really cost £30mn?
The £30 million number quoted by
LUL is made up of two principal items
trains and signalling. Two trains at £10mn
each and £10mn for signalling. A
new train would indeed cost £10
million and its not like buying a new
car. Typically LUL orders their trains
in batches so it is unlikely that they
ever would just buy new trains for one
service enhancement.
However when you they are upgrading the
line they would achieve a certain frequency
by buying a certain number of trains.
This frequency would be reduced if there
was a stop at Turnham Green and two extra
trains would need to be added to the order.
The alternative would be to take a marginal
reduction in your target frequency. Therefore
it is technically true that a Turnham
Green stop would "cost" £20
million. On the other hand you have
to set the marginal reduction in frequency
that would be caused by not buying two
trains against the benefit to the network
of having a stop. Remember this eventuality
only arises well into the future when
they are actually purchasing a new batch
of stock for the Piccadilly line.
At the moment no extra trains are needed
because LUL are operating well short of
their target of 30 trains per hour (and
therefore must have spare capacity) This
situation is likely to continue for the
next few years at least and possibly will
only be completely sorted out when there
is a general upgrade of the line..
The signals in this section of the line
are quite antiquated and due for an upgrade.
It is not clear whether the £10
million quoted is cost of this upgrade
in total. It does seem unlikely that the
signalling change necessary to maintain
frequencies on the line if a stop at Turnham
Green would cost that much. One former
LUL employee has estimated that the cost
would be around £100,000 for the
enhancements necessary in isolation but
if a Turnham Green stop was incorporated
into the general upgrade then the marginal
cost would effectively be zero.
Would LUL need
to buy two new trains to introduce a stop
today?
At the moment no, because LUL are operating
well below their target frequency of 30
trains per hour.
It
is possible they would need to buy new
trains just to operate at 30 trains per
hour even if there wasn't a stop at Turnham
Green.
The current stock of Piccadilly line is
86.5 trains. It is estimated that 85 trains
would need to be operational every day
to have a train stopping in the central
section of the line every 2 minutes. In
practise about 9 more trains would be
needed.
One solution to this is possibly to use
the Jubilee line stock that was mothballed
when the extension was built. This is
not particularly old - it was brought
into service in 1986 and it could operate
on the Piccadilly line. There are 15 of
these trains available which could possibly
allow a 30 trains per hour service to
be achieved with a stop at Turnham Green.
Would the frequency
of Piccadilly line trains really drop
from every two minutes to every three
minutes?
No - because Piccadilly line trains
are actually only operating every two
and a half minutes at peak times according
to their own timetable. This is because
their existing systems are unable to handle
greater frequencies. In fact the timetable
is being altered to reduce frequencies
at off peak times because of the timetable
has proved too demanding for the network.
Okay, would the
frequency of Piccadilly line trains drop
from two an a half minutes to every three
minutes?
Almost definitely yes. Existing
signalling at Turnham Green is not sophisticated
enough to hold a train very close to the
station so they have to wait a long way
back. This would lead to bunching of trains
and reduce frequency. In part this might
be mitigated by the fact that there is
often a hold-up at Acton Town because
of a change of drivers so the delay would
occur whether there was an extra stop
or not. The only way around this is improved
signalling and how feasible this is remains
unclear. There seems to be no good reason
why, as part of a general upgrade, the
specification for a stop at Turnham Green
could not be introduced. Under the Mayor's
plans this upgrade would occur in 2004.
As was stated above to introduce signalling
specifically for this change probably
wouldn't cost £10 mn but that is
not to say that the actual cost wouldn't
be prohibitive.
If a signal upgrade
was possible what would be the impact
on frequencies?
Assuming no extra trains were brought
into use then there would be an estimated
5% reduction in frequency at peak hours.
This translates into an estimated 6 extra
people in each carriage of the train.
If extra trains were brought on then the
amount of people on each train would remain
unchanged.
When will the
trains ever stop?
If the signalling was relatively cheap
and easy to upgrade for a stop at Turnham
Green (there is no conclusive evidence
that this is the case) LUL would probably
be able to introduce a stop with relatively
little impact on frequencies very soon.
However they may feel that the introduction
of a stop now would leave them short of
stock when they manage to upgrade their
systems to operate at 30 trains per hour
(i.e. every two minutes). Although
theoretically they could use the Jubilee
stock there maybe a good reason why this
is impractical. This would mean that
they would either have to plan for a reduced
level of frequency in the future or take
away the Turnham Green stop at a later
date.
In the longer term signals will be upgraded
and new trains will be bought regardless
whether there is a stop at Turnham Green.
The management of London Underground seem
to be entirely focussed on frequency which
may be a result of the way they are assessed.
This is not a bad thing in itself because
obviously more frequent trains means less
overcrowding and a safer network. However
from this perspective stopping at Turnham
Green becomes a pure cost i.e. it reduces
your return on investment because you
need more trains to meet you target frequencies.
It will be more difficult for LUL to maintain
this practise of focussing on one variable
when they come under the auspices of the
GLA. Whilst the GLA will be keen to see
LUL increase train frequencies they will
be more sensitive to other passenger needs
such as a stop at Turnham Green.
If
the GLA felt that the benefit of a stop
at Turnham Green outweighed the impact
on frequencies then there is no reason
that it couldn't commit in principle to
a stop being introduced as soon as Transport
for London (the GLA body that will oversee
the tube) takes over. How soon that would
lead to a trains actually stopping remains
unclear but 2015 seems an unlikely date.
Related
articles:
Ann
Keen's Statement on the Issue
Tim
Mack says GLA not LUL will decide
Campaign
not over according to Peter Eversden of
the Chiswick Protection Group
Chiswick
Chokes as Bureaucrats Bungle
Is
Turnham Green the Most Dangerous Station
on the Tube?
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