On Wed, 22 Dec 2004, Mrs Redboots wrote:

Tom Anderson wrote to uk.transport.london on Tue, 21 Dec 2004:

(Re Fenchurch Street & Tower Gateway DLR stations):

In any case, DLR are unlikely to close Tower Gateway station at its
current location; it's extremely useful.

Why?

I found it useful when I was commuting to Docklands on the days I went
from Streatham, as I could get a direct train into Blackfriars, then a
short ride on the District Line, and then a direct train towards East
India or Canning Town. I didn't have to faff about changing trains at
Westferry, or walking for miles around the Monument/Bank complex.

Nor would you with the new station - i'm not talking about closing the
Fenchurch Street DLR station (Tower Gateway), i'm talking about moving it
a few hundred metres - indeed, moving it closer to the tube station (Tower
Hill), as well as increasing the frequency of trains calling there.

However, it is due to be reduced to a single but lengthened platform as
part of the capacity improvement project, as the island platform would
become dangerously overcrowded.

When you say 'single', do you mean it will still be an island, or will
it become a single-face platform? I can't see the latter being great
for capacity, but if reverses aren't a limiting factor, i suppose it
would work.

The trains reverse now - they come into the platform (normally platform
2), and head out the way they came.

Right, but they've got two places to do it, one on either side of the
platform, which means you can have one train pulling out as another
arrives, which you can't with a single-faced platform. However, i think
the frequency and dwell time of DLR trains is sufficiently low that a
single face would be fine.

tom

--
All bloggers must die.

On Wed, 22 Dec 2004, Dave Arquati wrote:

Tom Anderson wrote:
On Tue, 21 Dec 2004, Dave Arquati wrote:

Tom Anderson wrote:

On Sun, 19 Dec 2004, John Rowland wrote:

"Tom Anderson" wrote in message
...

On Sat, 18 Dec 2004, Dave Arquati wrote:

I believe even in the tunnel to Bank for an underground station to
replace Tower Gateway, which was originally going to be closed in
favour of Bank, but DLR decided operationally that it was too
useful to close.

Do you have any (pointers to) more information on this?

The flat straight spot between two very steep curved sections is
quite obvious if you ride the DLR to or from Bank, especially if you
sit in the front.

Is that right after the junction with the Tower Gateway branch,
immediately south of Tower Gateway station? That's the only
likely-looking straight bit i can see on the (admittedly quite poor)
maps i can find. Although it is on the right tunnel, sadly, it's even
further from Fenchurch Street than Tower Gateway - although perhaps
closer to Tower Hill.

Many c2c trains now stop at either Limehouse or West Ham to provide
access to Docklands more rapidly than going into Fenchurch St and out
again.

Still, all things being equal (which they aren't) it would be preferable
to have better interchange, surely?

Yes, of course - but given the costs of changing the existing provision
(the flat, straight section of tunnel and existing Docklands area access
from Limehouse and West Ham) it wouldn't really stand up in a
cost-benefit analysis.

No, of course not. But i'm always hopeful!

In any case, DLR are unlikely to close Tower Gateway station at its
current location; it's extremely useful.

Why?

When there are operational problems at Bank (for example fire alerts,
Tube strikes, that sort of thing), trains can still get to/from the
City. That wouldn't necessarily be possible with an underground station
in the safeguarded location, as trains would have to reverse in the
sidings beyond Bank.

Could there not be a (and correct me if this is not what i mean) trailing
crossover? Like so:

----+----------
to Bank \ ### to Thatcherite nightmare wasteland
------+--------
Tower Moat
Station
or whatever they call it

So a train from the east could pull in to Tower X on the southern track,
then run on west, over the crossover, then reverse and pull into the
westbound platform.

I suppose the tunnels have already been built, and retrofitting this would
be hugely expensive.

Incidentally, and on a bit of a tangent, this arrangement would also work:

------+--------
/ ###
----+----------

With trains doing the actual reverse on the westbound track - you might
call this a right-rail reverse, and the other a wrong-rail reverse. Which
one is actually used in practice? Why?

It also provides additional reversing capacity in the City for Beckton
trains,

A few lines from here, you say reversing capacity isn't an issue!

and could be used to turn trains short if there is some operational
problem on the Isle of Dogs (although I don't know if that ever
happens!).

Not sure i get that. Where are these short-turned trains coming from and
going to? I can't see how Tower Gateway is any better than Bank / Tower
Moat for this.

However, it is due to be reduced to a single but lengthened platform as
part of the capacity improvement project, as the island platform would
become dangerously overcrowded.

When you say 'single', do you mean it will still be an island, or will it
become a single-face platform? I can't see the latter being great for
capacity, but if reverses aren't a limiting factor, i suppose it would
work.

I mean a single-faced platform (sorry, I didn't make that clear). This
is only really a capacity reduction of 25%, as 2 two-car platforms will
become one three-car platform. The problem is that the island platform
cannot be lengthened to accommodate additional passengers without being
widened - and there is no room to widen the viaduct. Reversals aren't a
huge issue on the DLR thanks to the computer control; the limiting
factor is how quickly you can disembark a trainload and embark the next
trainload, and that is partly limited by platform space.

Two faces still gives you more capacity, since you can be handling two
trains at once (sort of - trains can interfere with each other through the
crossover, which makes things slightly complicated).

There was once a plan to extend Tower Gateway over Minories into the
university building opposite, bringing it closer to Fenchurch Street,
but I don't know what happened to that idea.

Hey, maybe the real solution is to move Fenchurch Street Station down the
line a bit ...

tom

--
All bloggers must die.

Tom Anderson wrote:
Right, but they've got two places to do it, one on either side of the
platform, which means you can have one train pulling out as another
arrives, which you can't with a single-faced platform.

Except that unless my memory fails me, you can't actually do that at
Tower Gateway, as Royal Mint Street Junction is single-lead and not too
far off the platform ends. (So you'd get a very small improvement but
not much of one.)

On the other hand, if a train is stuck in the platform for whatever
reason, right now the next train can just pull into the other platform
-- if and when TG goes single-faced, the next train will have to wait
at RMSJ, blocking the line to Bank. That could be a bigger deal.

The layout of TG and RMSJ from memory:

|--------------------------*----*--*------------------------------------
***platform***XXXextnXXX / / \ to
Westferry
|========================= /
/---*----------------------------------
/ / RMSJ
/ /
---------------------------/ /
to Bank /
----------------------------/

Tom Anderson wrote:
On Wed, 22 Dec 2004, Dave Arquati wrote:
Tom Anderson wrote:
On Tue, 21 Dec 2004, Dave Arquati wrote:
Tom Anderson wrote:
On Sun, 19 Dec 2004, John Rowland wrote:
"Tom Anderson" wrote in message
...
On Sat, 18 Dec 2004, Dave Arquati wrote:

I believe even in the tunnel to Bank for an underground station to
replace Tower Gateway, which was originally going to be closed in
favour of Bank, but DLR decided operationally that it was too
useful to close.

Do you have any (pointers to) more information on this?

The flat straight spot between two very steep curved sections is
quite obvious if you ride the DLR to or from Bank, especially if you
sit in the front.

Is that right after the junction with the Tower Gateway branch,
immediately south of Tower Gateway station? That's the only
likely-looking straight bit i can see on the (admittedly quite poor)
maps i can find. Although it is on the right tunnel, sadly, it's even
further from Fenchurch Street than Tower Gateway - although perhaps
closer to Tower Hill.

Many c2c trains now stop at either Limehouse or West Ham to provide
access to Docklands more rapidly than going into Fenchurch St and out
again.

Still, all things being equal (which they aren't) it would be preferable
to have better interchange, surely?

Yes, of course - but given the costs of changing the existing provision
(the flat, straight section of tunnel and existing Docklands area access
from Limehouse and West Ham) it wouldn't really stand up in a
cost-benefit analysis.

No, of course not. But i'm always hopeful!

In any case, DLR are unlikely to close Tower Gateway station at its
current location; it's extremely useful.

Why?

When there are operational problems at Bank (for example fire alerts,
Tube strikes, that sort of thing), trains can still get to/from the
City. That wouldn't necessarily be possible with an underground station
in the safeguarded location, as trains would have to reverse in the
sidings beyond Bank.

Could there not be a (and correct me if this is not what i mean) trailing
crossover? Like so:

----+----------
to Bank \ ### to Thatcherite nightmare wasteland
------+--------
Tower Moat
Station
or whatever they call it

Hey, I like Docklands :-) If it weren't for Docklands, we wouldn't have
the fantastic DLR to prove that trains can work...

So a train from the east could pull in to Tower X on the southern track,
then run on west, over the crossover, then reverse and pull into the
westbound platform.

I suppose the tunnels have already been built, and retrofitting this would
be hugely expensive.

Bingo.

Incidentally, and on a bit of a tangent, this arrangement would also work:

------+--------
/ ###
----+----------

With trains doing the actual reverse on the westbound track - you might
call this a right-rail reverse, and the other a wrong-rail reverse. Which
one is actually used in practice? Why?

I have no idea... I suspect that usually a "right-rail" reverse is
preferred as firstly you don't confuse the passengers on the platform,
and secondly, sometimes you can't carry passengers over certain
crossovers. However, I know that reversals at South Harrow are "wrong-rail".

It also provides additional reversing capacity in the City for Beckton
trains,

A few lines from here, you say reversing capacity isn't an issue!

I don't really know what I'm talking about. Bank has quite a high
reversing capacity anyway as it has a reversing siding beyond the
station rather than a scissors crossover. Let's forget about reversing
capacity!

and could be used to turn trains short if there is some operational
problem on the Isle of Dogs (although I don't know if that ever
happens!).

Not sure i get that. Where are these short-turned trains coming from and
going to? I can't see how Tower Gateway is any better than Bank / Tower
Moat for this.

Tower Gateway is nearer to the Isle of Dogs than Bank (by 1km), so a
westbound train at Shadwell will return to Shadwell more quickly from
Tower Gateway than from Bank. So if a train is running "late" (rare on
the DLR) then it could be sent to Tower Gateway instead of Bank, and on
its return it would have made up about 2 minutes in its schedule.

Then again, like I said, I have no idea whether this actually ever
occurs in practice. I think 99.2% of DLR trains are on time so it might
not even happen!

I also just discovered that some weekend trains run from Tower Gateway
to Lewisham; that implies that Tower Gateway is considered useful for
tourists.

However, it is due to be reduced to a single but lengthened platform as
part of the capacity improvement project, as the island platform would
become dangerously overcrowded.

When you say 'single', do you mean it will still be an island, or will it
become a single-face platform? I can't see the latter being great for
capacity, but if reverses aren't a limiting factor, i suppose it would
work.

I mean a single-faced platform (sorry, I didn't make that clear). This
is only really a capacity reduction of 25%, as 2 two-car platforms will
become one three-car platform. The problem is that the island platform
cannot be lengthened to accommodate additional passengers without being
widened - and there is no room to widen the viaduct. Reversals aren't a
huge issue on the DLR thanks to the computer control; the limiting
factor is how quickly you can disembark a trainload and embark the next
trainload, and that is partly limited by platform space.

Two faces still gives you more capacity, since you can be handling two
trains at once (sort of - trains can interfere with each other through the
crossover, which makes things slightly complicated).

There was once a plan to extend Tower Gateway over Minories into the
university building opposite, bringing it closer to Fenchurch Street,
but I don't know what happened to that idea.

Hey, maybe the real solution is to move Fenchurch Street Station down the
line a bit ...

Well, you can already see the platforms at Fenchurch St from the
platforms at Tower Gateway. Someone could just build a footbridge, the
main problem being that Fenchurch St is a gated station.

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

On 22 Dec 2004, Alistair Bell wrote:

Tom Anderson wrote:

Right, but they've got two places to do it, one on either side of the
platform, which means you can have one train pulling out as another
arrives, which you can't with a single-faced platform.

Except that unless my memory fails me, you can't actually do that at
Tower Gateway, as Royal Mint Street Junction is single-lead and not too
far off the platform ends. (So you'd get a very small improvement but
not much of one.)

True. I tried to work it out exactly, but the maths makes my head hurt.

On the other hand, if a train is stuck in the platform for whatever
reason, right now the next train can just pull into the other platform
-- if and when TG goes single-faced, the next train will have to wait at
RMSJ, blocking the line to Bank. That could be a bigger deal.

Has that ever happened?

The layout of TG and RMSJ from memory:

I'm afraid your diagram's got somewhat jumbled:

|--------------------------*----*--*------------------------------------
***platform***XXXextnXXX / / \ to
Westferry
|========================= /
/---*----------------------------------
/ / RMSJ
/ /
---------------------------/ /
to Bank /
----------------------------/

I'm assuming you meant:

|--------------------------*----*--*----------------------------
***platform***XXXextnXXX / / \ to Westferry
|========================= / /---*--------------------------
/ / RMSJ
/ /
---------------------------/ /
to Bank /
----------------------------/

tom

--
Never attribute to malice that which can be adequately explained by stupidity -- Hanlon's Razor

John Ray wrote to uk.transport.london on Wed, 22 Dec 2004:

Mrs Redboots wrote:

The DLR station at Limehouse is actually designed for interchange with
C2C, and is announced as such.

The two lines are at the same height above the ground, but the
interchange (if I remember correctly) involves going down a flight of
stairs and then climbing up another!

Most of the DLR stations seem to be up at least one flight of stairs,
unless you use the lifts, which smell.
--
"Mrs Redboots"
http://www.amsmyth.demon.co.uk/
Website updated 18 December 2004

Tom Anderson wrote:
On Wed, 22 Dec 2004, Dave Arquati wrote:
(snip)
I mean a single-faced platform (sorry, I didn't make that clear). This
is only really a capacity reduction of 25%, as 2 two-car platforms will
become one three-car platform. The problem is that the island platform
cannot be lengthened to accommodate additional passengers without being
widened - and there is no room to widen the viaduct. Reversals aren't a
huge issue on the DLR thanks to the computer control; the limiting
factor is how quickly you can disembark a trainload and embark the next
trainload, and that is partly limited by platform space.


Two faces still gives you more capacity, since you can be handling two
trains at once (sort of - trains can interfere with each other through the
crossover, which makes things slightly complicated).

I forgot to reply to this. Two faces theoretically give you more *train*
capacity, but not necessarily more *passenger* capacity. If you can have
two trains in the station but passengers have difficulty actually
getting on and off trains because the platform is so crowded, then you
have a reduced passenger capacity; this in turn will lead to a reduced
train capacity because the dwell time will be very high.

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

Tom Anderson wrote to uk.transport.london on Thu, 23 Dec 2004:


On the other hand, if a train is stuck in the platform for whatever
reason, right now the next train can just pull into the other platform
-- if and when TG goes single-faced, the next train will have to wait at
RMSJ, blocking the line to Bank. That could be a bigger deal.

Has that ever happened?

The layout of TG and RMSJ from memory:

I've certainly seen a train stuck in the normal platform at Tower
Gateway, and the other platform was immediately brought into use.
--
"Mrs Redboots"
http://www.amsmyth.demon.co.uk/
Website updated 18 December 2004

Tom Anderson wrote:
On 22 Dec 2004, Alistair Bell wrote:


Tom Anderson wrote:


Right, but they've got two places to do it, one on either side of the
platform, which means you can have one train pulling out as another
arrives, which you can't with a single-faced platform.

Except that unless my memory fails me, you can't actually do that at
Tower Gateway, as Royal Mint Street Junction is single-lead and not too
far off the platform ends. (So you'd get a very small improvement but
not much of one.)


True. I tried to work it out exactly, but the maths makes my head hurt.

I've discovered some extra useful information, to do with the DLR
capacity enhancement which reduces the island platform to a single large
platform:

"The removal of a platform from Tower Gateway was unfortunate, because
temporary closures of Bank would put pressure on the single platform. If
Bank closed temporarily, 15 trains an hour could be turned round because
of track alterations outside the station, or trains could be turned at
Shadwell. There would be a holding track outside the station for failed
trains."
(from this PDF document: http://www.ltuc.org.uk/get_document.php?id=1613)


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

In message , Dave Arquati
writes
I have no idea... I suspect that usually a "right-rail" reverse is
preferred as firstly you don't confuse the passengers on the platform,
and secondly, sometimes you can't carry passengers over certain
crossovers. However, I know that reversals at South Harrow are
"wrong-rail".

Not always, you can go into either platform from the east.
--
Steve Fitzgerald has now left the building.
You will find him in London's Docklands, E16, UK
(please use the reply to address for email)