Victoria Line on Wednesday morning
 

On Wednesday morning, at aboutn 9.50a.m. there was some sort of
Victoria Line problem on the Northbound line into Victoria - according
to a station announcer a train was due to "come out of a siding"
(somewhere between Victoria and Pimlico?) to be the next Northbound
train but there was a signal problem, and the line became blocked.

So, for some reason the next Southbound train to arrive at Victoria was
terminated at Victoria, and all of us waiting on the Northbound
platform were directed onto that train. The train was evacuated of
angry Southbound passengers, the train sealed, carriage by carriage,
and then re-opened carriage by carriage for Northbound passengers to
board, all watched by furious Southbound passengers who then had to
wait on the platform. The driver changed ends and we all sat patiently
for a few minutes.

Then came an announcement that they could not get the signal to allow
that train to leave the Southbound platform in a Northerly direction. I
spoke to the driver, who confirmed that "I can't get the signal".

Then the train was evacuated for a second time, and both platforms then
became full of Northbound and Southbound passengers nicely mixed up!

A few minutes later came the announcement that "All Victoria Line
services are now suspended". There was then the inevitable mass exodus
of several hundred passengers angrily looking for other means of
transport at about 10.15a.m.

Two questions for those "in the know":

1. Was it inevitable that there would be difficulty in the Southbound
train trying to travel North out of the Southbound platform? For
example, maybe this was impossible because the next following
Southbound train was in block and therefore preventing any other train
from "reversing" into its block, even if only to use the cross-over to
the Northbound? If so, why did they even attempt to do so?

2. How on Earth could such a localised problem on a section South of
Victoria effectively paralyse the entire line in both directions?
Aren't there procedures in place to allow, for example (as presumably
was attempted here), turning trains at Victoria and then continuing a
Victoria - Walthamstow service, cutting out the Brixton section?

For all I know, the problem may have been rectified within minutes (it
certainly was by the time I arrived at Highbury an hour later, by bus),
but, never mind terrorist alerts, there seems a tendency to shut down
the entire line at the drop of a hat.

Marc.

Victoria Line on Wednesday morning
 

In article .com,
" writes
On Wednesday morning, at aboutn 9.50a.m. there was some sort of
Victoria Line problem on the Northbound line into Victoria - according
to a station announcer a train was due to "come out of a siding"
(somewhere between Victoria and Pimlico?)

At the south end of Victoria station.

to be the next Northbound
train but there was a signal problem, and the line became blocked.

Sounds like something prevented the points being restored to face the
northbound running line while, at the same time, preventing anything
coming out of the sidings. Offhand I can't see how a single failure
could cause that, but that may just be lack of imagination on my part.

So, for some reason the next Southbound train to arrive at Victoria was
terminated at Victoria, and all of us waiting on the Northbound
platform were directed onto that train.

Good thinking on someone's part. At this point you can't allow any more
trains north from Pimlico. So, unless you want to leave passengers in
tunnels for an unknown length of time, you're limited to 8 trains in
total south of Victoria (there being 4 stations with 2 platforms each).
Since it is possible to run the line as if Victoria was the southern
terminus, that would at least keep the service running.

The train was evacuated of
angry Southbound passengers, the train sealed, carriage by carriage,
and then re-opened carriage by carriage for Northbound passengers to
board, all watched by furious Southbound passengers who then had to
wait on the platform.

How would you do it without even more confusion?

Then came an announcement that they could not get the signal to allow
that train to leave the Southbound platform in a Northerly direction. I
spoke to the driver, who confirmed that "I can't get the signal".

Oh dear oh dear. Not a good day. Presumably the reversing crossover
failed in some way.

A few minutes later came the announcement that "All Victoria Line
services are now suspended".

Predictable.

1. Was it inevitable that there would be difficulty in the Southbound
train trying to travel North out of the Southbound platform?

No.

For
example, maybe this was impossible because the next following
Southbound train was in block and therefore preventing any other train
from "reversing" into its block, even if only to use the cross-over to
the Northbound?

The following train would be stopped at the previous signal or block
post, which would be before the crossovers. So I don't see that as an
explanation.

2. How on Earth could such a localised problem on a section South of
Victoria effectively paralyse the entire line in both directions?

See above. It wasn't one localised problem, it was two separate
problems.

Aren't there procedures in place to allow, for example (as presumably
was attempted here), turning trains at Victoria and then continuing a
Victoria - Walthamstow service, cutting out the Brixton section?

Yes, which is what you've described happening! It's just that those also
failed.

For all I know, the problem may have been rectified within minutes (it
certainly was by the time I arrived at Highbury an hour later, by bus),

It's possible that the line was cut back to Warren Street - Walthamstow;
IIRC, Warren Street is the next crossover back.

--
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:

Victoria Line on Wednesday morning
 

On 24 Nov 2005 16:12:45 -0800, "
wrote:

angry Southbound passengers
passengers angrily looking

Nobody is "mildly annoyed" these days....
--
Nick Cooper

[Carefully remove the detonators from my e-mail address to reply!]

The London Underground at War, and in Films & TV:
http://www.nickcooper.org.uk/

Victoria Line on Wednesday morning
 

Clive,

Many thanks for your informative reply. Yes, I suppose, on reflection
there were 2 problems, which were probably unconnected. An unfortunate
coincidence.

Nick, I was not "angry", just reisgned to my fate as another victim of
what one expects nowadays on the Underground.

Paradoxically, I used the Underground (Fulham Broadway to St. James'
Park) every day of my secondary school and NOT ONCE was I late on
account of Underground problems beween 1976 and 1984! Much as I would
have wanted otherwise.....

Marc.

Victoria Line on Wednesday morning
 

Clive D. W. Feather wrote:
It's possible that the line was cut back to Warren Street - Walthamstow;
IIRC, Warren Street is the next crossover back.

Thank god the builders of the JLE had the forsight to put in lots of
crossovers so the nonense we have to put up with on other lines
whereby huge swathes of the line is closed simply because of
a lack of crossovers to reverse trains at is mitigated. I sometimes
wonder if it was lack of money or lack of foresight that caused
so few to be built in the underground sections of tube lines and
in cases where there was deliberate removal of them such as at
Covent Garden on the piccadilly and Archway on the northern,
whether just plain stupidity was involved.

B2003

Victoria Line on Wednesday morning
 

On 24 Nov 2005 16:12:45 -0800, "
wrote:

On Wednesday morning, at aboutn 9.50a.m. there was some sort of
Victoria Line problem on the Northbound line into Victoria - according
to a station announcer a train was due to "come out of a siding"
(somewhere between Victoria and Pimlico?) to be the next Northbound
train but there was a signal problem, and the line became blocked.

[snip]

Two questions for those "in the know":

1. Was it inevitable that there would be difficulty in the Southbound
train trying to travel North out of the Southbound platform? For
example, maybe this was impossible because the next following
Southbound train was in block and therefore preventing any other train
from "reversing" into its block, even if only to use the cross-over to
the Northbound? If so, why did they even attempt to do so?

I would say it was not inevitable that the attempt to run north from the
s/b platform would fail because of the failure at the sidings. The two
ends of the station should run independently of each other.

It sounds to me, and I cannot recall what was in the internal daily
report, that there was a second failure that then prevented the intended
recovery strategy from working. It is the most sensible strategy at
Victoria if you are in the position of having the two sidings out of
service to the south because you can't get trains back out on to the n/b
tracks.

There is no point in sending trains to Brixton because you will end up
with a huge jam and given past incidents about trains stuck in tunnels
great attention is now paid to ensuring trains do not become stuck
between stations.

2. How on Earth could such a localised problem on a section South of
Victoria effectively paralyse the entire line in both directions?
Aren't there procedures in place to allow, for example (as presumably
was attempted here), turning trains at Victoria and then continuing a
Victoria - Walthamstow service, cutting out the Brixton section?

The decision to suspend is often the logical consequence when somewhere
like Victoria fails. It is so crucial to the line's operation that you
have to suspend, get the power off and allow the repair staff on to
track to undertake repairs. The other issue is traction current
sections which may not align with where the turnbacks / crossovers are.
Therefore you may need to suspend over a larger area to get the power
off.

Another point is that while loads of people are inconvenienced when a
line suspends it does provide a level of certainty about travel options
- i.e. the line is NOT running rather than it "might, possibly be
running to somewhere on the line at some point in time". I know this
seems perverse if you want to use the line but at least you are "forced"
to think about using another route.

If it's any consolation I hate it when the Vic Line falls over like this
as it's the main tube line to get me home. I do have about 10
contingency routes "up my sleeve" so I can keep moving if the worst
happens.
--
Paul C


Admits to working for London Underground!

Victoria Line on Wednesday morning
 

In article .com,
Boltar wrote:
Thank god the builders of the JLE had the forsight to put in lots of
crossovers so the nonense we have to put up with on other lines
whereby huge swathes of the line is closed simply because of
a lack of crossovers to reverse trains at is mitigated. I sometimes
wonder if it was lack of money or lack of foresight that caused
so few to be built in the underground sections of tube lines and
in cases where there was deliberate removal of them such as at
Covent Garden on the piccadilly and Archway on the northern,
whether just plain stupidity was involved.

In those cases, it was cost cutting. It's cheaper to maintain
'plain' line than a set of points. I understand the LuL is reversing
this, because they've realized that the operational flexability is
worth the cost.

However, the Archway still has a reversing siding - I was annoyed the other
day when the train that would have taken me to the delights of Church End
reversed there.

--
RIP Morph (1977-2005)

Victoria Line on Wednesday morning
 

On Fri, 25 Nov 2005, Boltar wrote:

Clive D. W. Feather wrote:

It's possible that the line was cut back to Warren Street - Walthamstow;
IIRC, Warren Street is the next crossover back.

Thank god the builders of the JLE had the forsight to put in lots of
crossovers so the nonense we have to put up with on other lines whereby
huge swathes of the line is closed simply because of a lack of
crossovers to reverse trains at is mitigated.

It's certainly a good thing that the JLE is built to a high level of
flexibility, but the Victoria line, which is what we were talking about
here, isn't actually that bad: you can reverse at Victoria, Warren Street,
King's Cross, Highbury & Islington and Seven Sisters, five out of the
line's sixteen stations!

Hmm. Can you actually reverse at H&I? There's a connection that should
allow it, according to the maps, but i've never heard of it happening.

And can you reverse in both directions at Victoria, Warren Street and
Seven Sisters? Again, the tracks would allow it, but what about the
signalling? Or is it all done manually?

tom

--
I content myself with the Speculative part [...], I care not for the
Practick. I seldom bring any thing to use, 'tis not my way. Knowledge
is my ultimate end. -- Sir Nicholas Gimcrack

Victoria Line on Wednesday morning
 

On Sat, 26 Nov 2005 03:25:25 +0000, Tom Anderson
wrote:

On Fri, 25 Nov 2005, Boltar wrote:

Clive D. W. Feather wrote:

It's possible that the line was cut back to Warren Street - Walthamstow;
IIRC, Warren Street is the next crossover back.

Thank god the builders of the JLE had the forsight to put in lots of
crossovers so the nonense we have to put up with on other lines whereby
huge swathes of the line is closed simply because of a lack of
crossovers to reverse trains at is mitigated.

It's certainly a good thing that the JLE is built to a high level of
flexibility, but the Victoria line, which is what we were talking about
here, isn't actually that bad: you can reverse at Victoria, Warren Street,
King's Cross, Highbury & Islington and Seven Sisters, five out of the
line's sixteen stations!

Hmm. Can you actually reverse at H&I? There's a connection that should
allow it, according to the maps, but i've never heard of it happening.

Reversal at Highbury certainly is done - usually if the line is
suspended due to an incident south of there.

And can you reverse in both directions at Victoria, Warren Street and
Seven Sisters? Again, the tracks would allow it, but what about the
signalling? Or is it all done manually?

Victoria is principally a south to north reversal - either via the
sidings to the south or the crossover. In theory you could run a train
north out of the n/b and reverse back over the crossover into the s/b
but I've never heard of that being done.

Warren St is south to north. I've never heard of it being done in the
reverse direction.

Seven Sisters - typically north to south via the sidings / depot road.
If a train fails in the s/b platform they can and do reverse it back
into the sidings. You can't head south from the central terminating
platform, only to the depot / sidings. I've also never heard of a n/b
train having left the Walthamstow platform, heading north and then
reversing back into the central terminating track at Seven Sisters.

Whether the "rare" moves are prevented by the signalling set up I simply
don't know.
--
Paul C


Admits to working for London Underground!

Victoria Line on Wednesday morning
 

Paul Corfield wrote:
Seven Sisters - typically north to south via the sidings / depot road.
If a train fails in the s/b platform they can and do reverse it back
into the sidings. You can't head south from the central terminating

Just out of curiousity , how far do the sidings at Brixton go? I've heard
the tunnel goes halfway to streatham (urban myth perhaps?) but how far
does the track go? Can you fit many trains down there or is it used for
storage of some sort?

B2003

Victoria Line on Wednesday morning
 

In message ,
writes

Just out of curiousity , how far do the sidings at Brixton go?

1200 feet beyond the platform end.

I've heard the tunnel goes halfway to streatham

More in the direction of Herne Hill - it ends under Somerleyton Road if
I remember correctly but, as I say, it stretches less than 1/4 of mile
from the station.

Can you fit many trains down there or is it used for storage of some
sort?

There's enough room to start the morning service from the south end of
the Victoria line - I thinks that's 8 trains in all (3 in each of the
tunnels and 2 in the platforms).

--
Paul Terry

Victoria Line on Wednesday morning
 

Hehehehe.... You hate it??

You want to right the IRFs......

Mal

"Paul Corfield" wrote in message
...
On 24 Nov 2005 16:12:45 -0800, "
wrote:

On Wednesday morning, at aboutn 9.50a.m. there was some sort of
Victoria Line problem on the Northbound line into Victoria - according
to a station announcer a train was due to "come out of a siding"
(somewhere between Victoria and Pimlico?) to be the next Northbound
train but there was a signal problem, and the line became blocked.

[snip]

Two questions for those "in the know":

1. Was it inevitable that there would be difficulty in the Southbound
train trying to travel North out of the Southbound platform? For
example, maybe this was impossible because the next following
Southbound train was in block and therefore preventing any other train
from "reversing" into its block, even if only to use the cross-over to
the Northbound? If so, why did they even attempt to do so?

I would say it was not inevitable that the attempt to run north from the
s/b platform would fail because of the failure at the sidings. The two
ends of the station should run independently of each other.

It sounds to me, and I cannot recall what was in the internal daily
report, that there was a second failure that then prevented the intended
recovery strategy from working. It is the most sensible strategy at
Victoria if you are in the position of having the two sidings out of
service to the south because you can't get trains back out on to the n/b
tracks.

There is no point in sending trains to Brixton because you will end up
with a huge jam and given past incidents about trains stuck in tunnels
great attention is now paid to ensuring trains do not become stuck
between stations.

2. How on Earth could such a localised problem on a section South of
Victoria effectively paralyse the entire line in both directions?
Aren't there procedures in place to allow, for example (as presumably
was attempted here), turning trains at Victoria and then continuing a
Victoria - Walthamstow service, cutting out the Brixton section?

The decision to suspend is often the logical consequence when somewhere
like Victoria fails. It is so crucial to the line's operation that you
have to suspend, get the power off and allow the repair staff on to
track to undertake repairs. The other issue is traction current
sections which may not align with where the turnbacks / crossovers are.
Therefore you may need to suspend over a larger area to get the power
off.

Another point is that while loads of people are inconvenienced when a
line suspends it does provide a level of certainty about travel options
- i.e. the line is NOT running rather than it "might, possibly be
running to somewhere on the line at some point in time". I know this
seems perverse if you want to use the line but at least you are "forced"
to think about using another route.

If it's any consolation I hate it when the Vic Line falls over like this
as it's the main tube line to get me home. I do have about 10
contingency routes "up my sleeve" so I can keep moving if the worst
happens.
--
Paul C


Admits to working for London Underground!

Victoria Line on Wednesday morning
 

Urban myth i am afraid.
The sidings can take 1 train each. In an emergency a secind train can be
fitted into the sidings but its not a signal move, its done under rule only
under exceptional situations, usually to enable trains to enter Brixton and
disgorge customers. It was done on during the 2 attacks.

Its a shame the system at Vic failed to work correctly. If it had we could
have had a service running. As it was, our private contractors couldn't find
the problem....but thats another thread!

Mal
wrote in message
...
Paul Corfield wrote:
Seven Sisters - typically north to south via the sidings / depot road.
If a train fails in the s/b platform they can and do reverse it back
into the sidings. You can't head south from the central terminating

Just out of curiousity , how far do the sidings at Brixton go? I've heard
the tunnel goes halfway to streatham (urban myth perhaps?) but how far
does the track go? Can you fit many trains down there or is it used for
storage of some sort?

B2003

Victoria Line on Wednesday morning
 

On Sat, 26 Nov 2005 18:54:55 GMT, "Mal"
wrote:

"Paul Corfield" wrote in message
.. .
On 24 Nov 2005 16:12:45 -0800, "
wrote:

If it's any consolation I hate it when the Vic Line falls over like this
as it's the main tube line to get me home. I do have about 10
contingency routes "up my sleeve" so I can keep moving if the worst
happens.

Hehehehe.... You hate it??

You want to right the IRFs......

Well I get to read enough of them in JNP land that I don't really want
to add in BCV as well.

--
Paul C


Admits to working for London Underground!

Victoria Line on Wednesday morning
 

In article ,
(Paul Corfield) wrote:

And can you reverse in both directions at Victoria, Warren Street
and Seven Sisters? Again, the tracks would allow it, but what about
the signalling? Or is it all done manually?

Victoria is principally a south to north reversal - either via the
sidings to the south or the crossover. In theory you could run a train
north out of the n/b and reverse back over the crossover into the s/b
but I've never heard of that being done.

Victoria was built with a scissors crossover at the North end, wasn;t
it? Why on earth did they remove it?

--
Colin Rosenstiel

Victoria Line on Wednesday morning
 

Thats terrible.....i meant write....... bugger!

Mal


"Paul Corfield" wrote in message
...
On Sat, 26 Nov 2005 18:54:55 GMT, "Mal"
wrote:

"Paul Corfield" wrote in message
. ..
On 24 Nov 2005 16:12:45 -0800, "
wrote:

If it's any consolation I hate it when the Vic Line falls over like this
as it's the main tube line to get me home. I do have about 10
contingency routes "up my sleeve" so I can keep moving if the worst
happens.

Hehehehe.... You hate it??

You want to right the IRFs......

Well I get to read enough of them in JNP land that I don't really want
to add in BCV as well.

--
Paul C


Admits to working for London Underground!

Victoria Line on Wednesday morning
 

On Sat, 26 Nov 2005, Paul Corfield wrote:

On Sat, 26 Nov 2005 03:25:25 +0000, Tom Anderson
wrote:

And can you reverse in both directions at Victoria, Warren Street and
Seven Sisters?

[snipped]

Whether the "rare" moves are prevented by the signalling set up I simply
don't know.

Fair enough. Cheers for the info!

tom

--
This should be on ox.boring, shouldn't it?

Victoria Line on Wednesday morning
 

On Sat, 26 Nov 2005 21:38 +0000 (GMT Standard Time),
(Colin Rosenstiel) wrote:

[Victoria line - Victoria line layout]

Victoria was built with a scissors crossover at the North end, wasn;t
it? Why on earth did they remove it?

I think you're right. No idea why they were removed.
--
Paul C


Admits to working for London Underground!

Victoria Line on Wednesday morning
 

In article ,
(Paul Corfield) wrote:

On Sat, 26 Nov 2005 21:38 +0000 (GMT Standard Time),
(Colin Rosenstiel) wrote:

[Victoria line - Victoria line layout]

Victoria was built with a scissors crossover at the North end,
wasn;t it? Why on earth did they remove it?

I think you're right. No idea why they were removed.

It. The trailing crossover was left in the crossover cavern.

--
Colin Rosenstiel

Victoria Line on Wednesday morning
 

Paul Corfield wrote:
On Sat, 26 Nov 2005 21:38 +0000 (GMT Standard Time),
(Colin Rosenstiel) wrote:

[Victoria line - Victoria line layout]

Victoria was built with a scissors crossover at the North end, wasn;t
it? Why on earth did they remove it?

I think you're right. No idea why they were removed.

Because Victoria has got a second scissors crossover south of the
station and two central reversing sidings. When the service is buggered
from Victoria to Brixton it can be used to reverse the southbound
service. The original scissors crossover (just like the one that used
to be at Highbury) is thus redundant.

http://www.trainweb.org/tubeprune/Vi...en%20Pk-rm.gif refers.

Victoria Line on Wednesday morning
 

In article .com,
(TheOneKEA) wrote:

Paul Corfield wrote:
On Sat, 26 Nov 2005 21:38 +0000 (GMT Standard Time),
(Colin Rosenstiel) wrote:

[Victoria line - Victoria line layout]

Victoria was built with a scissors crossover at the North end,
wasn;t it? Why on earth did they remove it?

I think you're right. No idea why they were removed.

Because Victoria has got a second scissors crossover south of the
station and two central reversing sidings. When the service is
buggered from Victoria to Brixton it can be used to reverse the
southbound service. The original scissors crossover (just like the one
that used to be at Highbury) is thus redundant.

http://www.trainweb.org/tubeprune/Vi...en%20Pk-rm.gif refers.

I appreciate it's redundant, but then it turns out not to be so on
occasion when other equipment fails. Some redundancy makes it easier to
cope with failures.

My surprise is that the facility was removed having been installed. It
would have cost very little just to leave it there.

--
Colin Rosenstiel

Victoria Line on Wednesday morning
 

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

http://www.trainweb.org/tubeprune/Vi...en%20Pk-rm.gif refers.

I appreciate it's redundant, but then it turns out not to be so on
occasion when other equipment fails. Some redundancy makes it easier to
cope with failures.

True, but in theory the simultaneous failure of the signalling in
Victoria South Sidings and the trailing crossover north of the station
should not happen. The fact that it did does not mean that having a
scissors crossover in position would have changed anything.


My surprise is that the facility was removed having been installed. It
would have cost very little just to leave it there.

Not necessarily - if that were the case the scissors crossover west of
Liverpool Street (Central) would not have been simplified either, and
yet it was - and Liverpool Street has the same arrangement as Victoria.

Victoria Line on Wednesday morning
 

In article , Tom
Anderson writes
And can you reverse in both directions at Victoria, Warren Street and
Seven Sisters? Again, the tracks would allow it, but what about the
signalling?

From the diagram that Tubeprune posted, you can do it at Victoria: for
north-to-south, run north out of the platform to behind VF16, then
reverse into the southbound platform.

Going to his site: you can do it at Warren Street. For north-to-south,
run north out of the platform to behind VG8, then reverse into the
southbound platform. For south-to-north, simply run directly over the
crossover when given the road by VG4.

Seven Sisters: you can only do south-to-north from platform 4. Either:
* no route indicator at VL6, forward to VL7, change ends, signal VL20
takes you over the scissors to VL19 which protects the entrance to
the southbound platform.
* right-hand indicator at VL6, forward over the crossover to a fixed red
light behind VL22A, change ends, signals VL22A and VL22B take you
straight to VL19.

North-to-south is harder but possible: into platform 5, change ends,
signal VL8 takes you on to the depot exit road, over the scissors, and
up to VL7. Change ends again, pass VL20 at danger with permission[*]
and run forward to the fixed red light at the end of platform 4. Change
ends a final time and depart normally (VL6 with left-hand junction
indicator).
[*] VL20 is not shown as having a junction indicator. I'm assuming,
therefore, that the only route from it leads to VL19. It could be,
however, that the only route leads to platform 4. In which case the
first of my south-to-north cases doesn't apply and north-to-south
involves all signalled moves.

--
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:

Victoria Line on Wednesday morning
 

In article , I wrote:
Seven Sisters: you can only do south-to-north from platform 4. Either:

Checking an old rulebook, I have some amendments to make:

* no route indicator at VL6, forward to VL7, change ends, signal VL20
takes you over the scissors to VL19 which protects the entrance to
the southbound platform.
* right-hand indicator at VL6, forward over the crossover to a fixed red
light behind VL22A, change ends, signals VL22A and VL22B take you
straight to VL19.

This is correct, except that the fixed red is placed so that VL22A will
be mid-train and can be ignored.

North-to-south is harder but possible: into platform 5, change ends,
signal VL8 takes you on to the depot exit road, over the scissors, and
up to VL7.

This is wrong. VL8 doesn't have a junction indicator, but nevertheless
can clear for two routes: either to VL7 on the depot entry road (62
road) or to the fixed red on the depot exit road (63 road). VL22B also
doesn't have an indicator but can clear for routes to either platform 4
(northbound) or 5 (southbound). So the north-to-south reversal is done
by: into platform 5, change ends, VL8 takes you to the fixed red on 63
road, change ends, VL22B takes you over the crossover and into platform
4, change ends, depart normally (VL6 with left-hand indicator).

[*] VL20 is not shown as having a junction indicator. I'm assuming,
therefore, that the only route from it leads to VL19.

This is correct.

--
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: