MIG wrote:
Dave Arquati wrote:
MIG wrote:
Dave Arquati wrote:
MIG wrote:
Dave Arquati wrote:
MIG wrote:
John B wrote:
Kev wrote:
This does sound like the thin end of the wedge. Ask people who used to
use the Watford Junc to Broad St (Liverpool St) and Watford to Croxley
service what they think of this.

OK, so in the first case a poor frequency service has been replaced
partly with the current NLL clockface 4tph timetable (set for further
improvements under TfL Rail) and will be replaced further with the ELLX
between Dalston and Shoreditch. In the second case, the link is set to
be rebuilt with more useful connections.

During London's decades of stagnation and decline, many useful rail
links were short-sightedly destroyed. The ideological antipathy of a
progression of governments and transport ministers towards public
transport didn't help matters.

However, it's now clear that the default mode for public transport in
London is one of expansion not contraction. Since Mill Hill East isn't
an Aldwych or an Ongar but somewhere with decent loadings, it would
therefore be hard to see why anyone would choose to close it...
But once it loses the through service it will have poor loadings.
Aldwych is right in the centre of London, but that didn't save it. I
don't suppose for a moment it would have closed if it had a through
service (or why not close Temple, St Pauls or Chancery Lane?).
Not sure of the logic here - St Paul's and Chancery Lane are extremely
busy during the week.
I was mentioning non-interchange stations that have a through service,
in the same general area as Aldwych, which didn't, and wasn't as busy.
I'm suggesting that the lack of through service reduced demand for
Aldwych rather than its location.
As other posters have suggested, Aldwych was probably doomed from its
birth. If Aldwych were reopened today with through services to
Cockfosters (which in itself is physically difficult), I think demand
would still be poor for two reasons:
1. The frequency with which Aldwych could be served would be limited by
capacity considerations on the rest of the line (it's not as though you
can just slot extra trains in the timetable between Holborn and Arnos
Grove, and the existing trains are busy with people heading to and from
places like Piccadilly Circus). In turn, sending trains to Aldwych would
pose reliability problems.
2. Even if served by a relatively high frequency, it's just too near
other Piccadilly stations to be particularly useful - even Holborn is
only a few minutes' walk away, and Covent Garden is much more useful for
the key theatre-going market.

I think we are both saying that the inevitable poor service made the
station unattractive. The poor service at Alwych follows from it being
on a stub with necessarily either a shuttle or infrequent through
service. A station on an imaginary through line at that location might
well have been popular.
I think we're getting the concepts of through *services* and through
*lines* muddled up here. I was saying that a through *service* to
Aldwych would have never have been able to attract high levels of
demand. A through *line* is an entirely different kettle of fish.


I don't really see why the distinction matters in this regard. If you
can get on at a station near where you are and there is a frequent
service that goes a long way without changing after one stop, the
service is more attractive than if you always have to change after one
stop or if the service is infrequent.

OK, I understand how you are equating a through service to a through
line (in terms of destinations served).

However, I maintain that the catchment area of the station is the
limiting factor. Even if Mill Hill East had a direct service to every
single station in central London, demand could only reach a certain
level because there are only a certain number of trip generators (e.g.
households or workplaces) within the catchment of the station, and
because those direct services will only save a certain amount of time
over services involving changes.

I think we're going around in circles with this though. The argument was
initially that Aldwych had an unattractive service, which made it
unpopular, which led to closure, and that therefore the same will happen
to Mill Hill East.

I disagree with this argument. Consider the sequence "through service"
- "shuttle service" - "closure".

For Aldwych, the through service is hypothetical, but we'll consider it
anyway. Through service results in a certain level of demand (q1) from
the surrounding area for Underground services.

I propose that this level of demand is related to the number of
destinations available, which I also propose is measured as the number
of trip attractors within a fixed number of generalised minutes (e.g.
45) - by which I mean taking into account penalties for interchanges,
walking, waiting and the like (e.g. an interchange is unattractive, so
might attract a hypothetical penalty of 10 minutes, plus however much
time it actually takes to change trains).

When the through service is reduced to a shuttle service, there is a
reduction in the level of demand for Tube services, which is related to
the reduction in number of destinations available (e.g. within 45
generalised minutes). *However*, this reduction is small, because the
closeness of other Tube stations like Covent Garden means that in
reality, the number of destinations available doesn't actually decrease
very much.

Now the shuttle service is reduced to NO service. There is another
reduction in demand for Tube services from the local area, because there
is a reduction in the number of destinations available by my measure.
However, once again, this reduction is small because there are many
alternatives. The case for closure is easily made, because of the small
drop in demand for Tube services.

Turning to Mill Hill East, we have a through service. Reducing this
through service to a shuttle will decrease the number of destinations by
my measure, as there is a new interchange penalty and additional waiting
time. This will reduce demand for Tube services from the area by an
amount related to the decrease in number of destinations available
within 45 generalised minutes.

This is where my argument comes in. Reducing this shuttle service to NO
service through closure would reduce the demand for Tube services from
the area around MHE proportionally MUCH more than for Aldwych, because
there would be a VAST reduction in the number of destinations available
from the MHE area compared to the small reduction at Aldwych.

The argument for reducing from a through service to a shuttle hinges on
the size of the reduction in available destinations within the
appropriate time limit. This reduction will be smaller than the
reduction from closure, because although creating a shuttle service
results in a penalty, destinations are still available - whereas
reducing from a shuttle to closure means that, if no alternative
stations are available, virtually no destinations are available.

The means of measuring the inconvenience caused to Mill Hill East users
is through valuation of the increases in the generalised time of their
journeys (the valuation resulting in a generalised cost for each user
based on their value of time). The total increase in generalised cost of
all journeys from Mill Mill East will be a monetary quantity.

It's then necessary to determine how much time all other Northern line
users will save from improved frequency (to High Barnet) and reliability
(across the line). This can then be valued in a similar way to produce
an estimated decrease in generalised cost for each user, and the total
decrease across all users will also be a monetary quantity.

If the first quantity (costs to MHE users) is lower than the second
quantity (benefits to all other users), then the move is a good one to make.

You have explained why the service from Aldwych is inevitably
unattractive, relating to the nature of the branch. The
unattractiveness of the service makes the station unpopular, whatever
the reason.

The proposed changes will go a long way towards making Mill Hill East
unpopular as well, always having to change trains after one stop and
cross over a bridge (unless there is going to be a reversing manoeuvre,
which certainly won't help reliability).

Once people stop using it in the off-peak, there will be an excuse to
cut it to peak only. Once it's peak only, people will drive to
Finchley Central so that they can get home if they happen to stay late
after work, and then MHE will close. It's a familiar pattern.

MHE will close if the costs to MHE users of closure are less than any
benefits that might accrue to other PT users because of its closure
(from spending the money used to run the branch elsewhere). In either
case - it would be justified (shock horror!).

Personally, I don't think the costs to MHE users of closure *would* be
lower than the benefits from the closure, so I don't think the branch
will be closed.

--
Dave Arquati
Imperial College, SW7
www.alwaystouchout.com - Transport projects in London