Dr Ivan D. Reid wrote:
http://www.tfl.gov.uk/tfl/press-cent...t.asp?prID=895

Incidentally, how is the line going to look once T5 is opened? Is it
still going to be a loop, with three stations (T4, T5, T123 in that
order from central London), or is the line going to split after Hatton
Cross with some trains going to T4 and some to T123 & T5?

Patrick

wrote:

Dr Ivan D. Reid wrote:
http://www.tfl.gov.uk/tfl/press-cent...t.asp?prID=895

Incidentally, how is the line going to look once T5 is opened? Is it
still going to be a loop, with three stations (T4, T5, T123 in that
order from central London), or is the line going to split after Hatton
Cross with some trains going to T4 and some to T123 & T5?

Patrick

It's the latter AIUI - i.e. trains will run either:

(1) Hatton Cross - T4 - T123 - Hatton Cross in the loop
or
(2) Hatton Cross - T123 - T5 where they'll terminate and then reverse.

The service will be split half/half. Those going to T123 will find
themselves there quicker on a train that goes to T5, as they won't have
to go round the loop. In practice I guess the time penalty for being on
a T4 loop train won't be that great so maybe just a few savvy
passengers with light or no luggage will hop between trains to take
advantage of this.

I've read that the T5 station will be staffed by BAA personnel, I guess
because they've entirely paid for the new Picadilly line link and
station to T5. I wonder how well they'll do in dispensing good advice
about public transport in London, and explaining the advantages of the
Oyster card and various other tickets and selling them to punters.

On 22 Sep 2006 01:34:21 -0700, Mizter T wrote:

It's the latter AIUI - i.e. trains will run either:

(1) Hatton Cross - T4 - T123 - Hatton Cross in the loop
or
(2) Hatton Cross - T123 - T5 where they'll terminate and then reverse.

The service will be split half/half.

Isn't it 2/3 T5 vs 1/3 T4? Or perhaps I'm imagining that.

Those going to T123 will find
themselves there quicker on a train that goes to T5, as they won't have
to go round the loop. In practice I guess the time penalty for being on
a T4 loop train won't be that great so maybe just a few savvy
passengers with light or no luggage will hop between trains to take
advantage of this.

I remember reading that T4 trains will have a layover in the platform
at T4 station, so for T123 it would probably be quicker to wait 5
minutes and catch the following T5 train.

ISTM that it would be better to reverse the direction that trains go
around the loop (and still lay over at T4). This would avoid the above
problem, and effectively increase the service frequency to T123 by 50%
(at the expense of effectively reducing it *from* T123, but in that
direction people aren't under time pressure to catch flights).

Slightly more radically, they could even close part of the loop,
running trains either CL-HX-T123-T4-T123-HX-CL, or CL-HX-T4-HX-CL
(where CL = Central London and HX = Hatton Cross). This would simplify
the line map and service pattern.

asdf wrote:

ISTM that it would be better to reverse the direction that trains go
around the loop (and still lay over at T4). This would avoid the above
problem, and effectively increase the service frequency to T123 by 50%
(at the expense of effectively reducing it *from* T123, but in that
direction people aren't under time pressure to catch flights).

Slightly more radically, they could even close part of the loop,
running trains either CL-HX-T123-T4-T123-HX-CL, or CL-HX-T4-HX-CL
(where CL = Central London and HX = Hatton Cross). This would simplify
the line map and service pattern.

They should shut Terminal 4 (station and terminal) until T1, T2, T3 and T5
are all operating to capacity, which will be years away.

John Rowland wrote:
asdf wrote:
ISTM that it would be better to reverse the direction that trains go
around the loop (and still lay over at T4). This would avoid the above
problem, and effectively increase the service frequency to T123 by 50%
(at the expense of effectively reducing it *from* T123, but in that
direction people aren't under time pressure to catch flights).

Slightly more radically, they could even close part of the loop,
running trains either CL-HX-T123-T4-T123-HX-CL, or CL-HX-T4-HX-CL
(where CL = Central London and HX = Hatton Cross). This would simplify
the line map and service pattern.

They should shut Terminal 4 (station and terminal) until T1, T2, T3 and T5
are all operating to capacity, which will be years away.

No, they should (and apparently will) shut and demolish T2 (the oldest
and most crowded/cramped facility) once T5 opens. One of the airline
alliances - Skyteam? - is going into T4; it'll make connections much
simpler.


--

Stephen

BUFFY: Hey Ken, wanna see my impression of Ghandi?
*thwump*
LILY: Ghandi?
BUFFY: Well, you know. If he was really ****ed off.

In article , asdf
writes
It's the latter AIUI - i.e. trains will run either:
(1) Hatton Cross - T4 - T123 - Hatton Cross in the loop
or
(2) Hatton Cross - T123 - T5 where they'll terminate and then reverse.

That's forced by the physical layout:

T5 ---------*-- T123 ---------------* HX ----- London
/ /
| /
\ /
\-------- T4 -------/

ISTM that it would be better to reverse the direction that trains go
around the loop (and still lay over at T4).

If you do that then London-bound trains will have to cross the westbound
line on the level, putting constraints on operations. Anyway, I don't
think that there's room west of Hatton Cross for a crossover to the
eastbound track (the junction is officially 90m from the mid-point of
the station, and a crossover requires at least 40m). So now you're
talking major reconstruction as well as resignalling the loop (which is
signalled one-way only).

Slightly more radically, they could even close part of the loop,
running trains either CL-HX-T123-T4-T123-HX-CL, or CL-HX-T4-HX-CL
(where CL = Central London and HX = Hatton Cross). This would simplify
the line map and service pattern.

The latter has the above problem. The former has the problem that the
single line between T3 and T4 puts heavy constraints on how frequent the
trains can be. Probably 3tph would be the limit.

[Memory says this was covered in Underground News recently.]

--
Clive D.W. Feather | Home:
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Fax: +44 870 051 9937 | Work:
Please reply to the Reply-To address, which is:

Clive D. W. Feather wrote:
That's forced by the physical layout:

T5 ---------*-- T123 ---------------* HX ----- London
/ /
| /
\ /
\-------- T4 -------/


Probably a stupid question, but why was the decision taken to construct
the line in that layout, rather than extending the loop so trains would
call HX, T4, T5, T123?

Patrick

In article .com,
() wrote:

Clive D. W. Feather wrote:
That's forced by the physical layout:

T5 ---------*-- T123 ---------------* HX ----- London
/ /
| /
\ /
\-------- T4 -------/


Probably a stupid question, but why was the decision taken to
construct the line in that layout, rather than extending the loop so
trains would call HX, T4, T5, T123?

Geography? Have you looked where Terminals 4 and 5 actually are?

--
Colin Rosenstiel

Colin Rosenstiel wrote:
In article .com,
() wrote:

Clive D. W. Feather wrote:
That's forced by the physical layout:

T5 ---------*-- T123 ---------------* HX ----- London
/ /
| /
\ /
\-------- T4 -------/


Probably a stupid question, but why was the decision taken to
construct the line in that layout, rather than extending the loop so
trains would call HX, T4, T5, T123?

Geography? Have you looked where Terminals 4 and 5 actually are?

Thanks for that informative reponse.

Are the terminals really so far apart that a three station loop would
have been impractical? It just seems a more logical service pattern
than some loop, some terminating.

Patrick

In article .com,
writes
Probably a stupid question, but why was the decision taken to construct
the line in that layout, rather than extending the loop so trains would
call HX, T4, T5, T123?

Terminal 5 is a *long* way west of Terminals 123 (2.3km). The run from
Terminal 4 round to T123 is already 4.4km, and most of that would have
to be abandoned. So you'd need about 6km of new tunnel for the loop as
well as the 2km actually dug.

--
Clive D.W. Feather | Home:
Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Please reply to the Reply-To address, which is: