London Bridge reconstruction works

[Bald Rick]

Also, significantly, such a proposal would not have realised any additional capacity. And London Bridge would still have needed resignalling, and the station would still have needed rebuilding, as it is all knackered.

 

[Peter Sarf]

I can see that if tunnels were considered it could become a case of where do you stop. Could end up tunnelling further North and South of my proposed tunnel. That could lead to the point where one would be left with the existing core unused which would be daft !. I suppose the factor is what is the minimum work required North and South of the central core of Thameslink (i.e. City Thameslink to St Pancras International) to fill the capacity of the central core.

As regards the maximum capacity being achieved I can see the limiting factor in what is done will be the conflicting junction just to the South of Blackfriars now that through Thameslink services are expected to run from/to the Elephant and Castle direction rather than terminating. I was considering how to get round that.

Also trying to remember if the Bermondsey dive under completely removes conflicts there for Thameslink (Up Thameselink from Lewisham-ish crossing Down Croydon Thameslink). I think it does avoid those conflicts ?.

I suppose the main advantage would have been less disruption unless London Bridge really did need all that re-building. Hard to justify the cost anyway.

 

[NotATrainspott]

I can see that if tunnels were considered it could become a case of where do you stop. Could end up tunnelling further North and South of my proposed tunnel. That could lead to the point where one would be left with the existing core unused which would be daft !. I suppose the factor is what is the minimum work required North and South of the central core of Thameslink (i.e. City Thameslink to St Pancras International) to fill the capacity of the central core.

As regards the maximum capacity being achieved I can see the limiting factor in what is done will be the conflicting junction just to the South of Blackfriars now that through Thameslink services are expected to run from/to the Elephant and Castle direction rather than terminating. I was considering how to get round that.

Also trying to remember if the Bermondsey dive under completely removes conflicts there for Thameslink (Up Thameselink from Lewisham-ish crossing Down Croydon Thameslink). I think it does avoid those conflicts ?.

I suppose the main advantage would have been less disruption unless London Bridge really did need all that re-building. Hard to justify the cost anyway.

Here's the diagram of the layout before and after works are done. After London Bridge, there is full grade-separation onto the Southern tracks but not onto the Southeastern ones.

 

[Bald Rick]

That's a very old diagram; whilst it shows the principles of the changes and correctly depicts the grade separation, the new layout itself is different to that shown.

 

[QueensCurve]

As regards the maximum capacity being achieved I can see the limiting factor in what is done will be the conflicting junction just to the South of Blackfriars now that through Thameslink services are expected to run from/to the Elephant and Castle direction rather than terminating. I was considering how to get round that.

It seems incredible that so much work is being put in to remove conflicting movements at Bermonsey and London Bridge when that flat junction (Southward Jct?) will remain so close to the "Thameslink Core".

Looking at the junction on Google Maps, it does seem as if a burrowing junction would be possible at that point.

Interesting that no work there has been proposed.

 

[Class 170101]

It seems incredible that so much work is being put in to remove conflicting movements at Bermonsey and London Bridge when that flat junction (Southward Jct?) will remain so close to the "Thameslink Core".

Looking at the junction on Google Maps, it does seem as if a burrowing junction would be possible at that point.

Interesting that no work there has been proposed.

Bear in mind whats underground that Google maps doesn't and cannot possibly hope to show. Jubilee Line, W&C and Utilities etc.

 

[swt_passenger]

Bear in mind whats underground that Google maps doesn't and cannot possibly hope to show. Jubilee Line, W&C and Utilities etc.

I think the idea proposed here is to burrow from the lower viaduct to the other higher one. You wouldn't ever go underground as such. In other words demolish part of the gradually sloping viaduct taking the east to north curve and keep the up T/L from London Br at its original level and then thread the line under the T/L down line to Elephant and Castle.

None of the lines in the immediate area are at real ground level. The potential problem is that some of the running junctions would be lost.

 

[Bald Rick]

It seems incredible that so much work is being put in to remove conflicting movements at Bermonsey and London Bridge when that flat junction (Southward Jct?) will remain so close to the "Thameslink Core".

Looking at the junction on Google Maps, it does seem as if a burrowing junction would be possible at that point.

Interesting that no work there has been proposed.

It's Blackfriars Junction.

And it really isn't a problem. Metropolitan Junction does, and will continue to, deal with 25% more trains per hour without a problem.

 

[Peter Sarf]

I think the idea proposed here is to burrow from the lower viaduct to the other higher one. You wouldn't ever go underground as such. In other words demolish part of the gradually sloping viaduct taking the east to north curve and keep the up T/L from London Br at its original level and then thread the line under the T/L down line to Elephant and Castle.

None of the lines in the immediate area are at real ground level. The potential problem is that some of the running junctions would be lost.

Yes I have looked at this while passing several times on Thameslink trains. The Blackfriars-South route is well above ground level. It passes over the the Charing Cross-London Bridge route which themselves are high enough above already. To get the non conflicting junction would require surgery to brick viaducts !. It would mean removing half of the ramp alongside the Charing Cross lines (blue) so that the Green Blackfriars bound line goes under the two green lines that come to/from Elephant and Castle (alongside the yellow lines).

I have also noticed that there appears to be an extra space under the Blackfriars-Elephant and Castle lines just to the North of the Charing Cross (blue) lines. Its as though there used to be a line (or two) from Charing Cross towards London bridge that came under the green+yellow lines as the others do BUT ran along the North side of the green ramp. That would have achieved a non conflicting junction unravelling some of what the Bermondsey dive under is supposed to do. Cannot really be true but its looks possible that there used to be something there as that is where the temporary looking Network rail offices were built. !.

EDIT :- Oh and thanks for the maps "NotATranspott" in post 453.

 

[MikeWh]

I have also noticed that there appears to be an extra space under the Blackfriars-Elephant and Castle lines just to the North of the Charing Cross (blue) lines. Its as though there used to be a line (or two) from Charing Cross towards London bridge that came under the green+yellow lines as the others do BUT ran along the North side of the green ramp. That would have achieved a non conflicting junction unravelling some of what the Bermondsey dive under is supposed to do. Cannot really be true but its looks possible that there used to be something there as that is where the temporary looking Network rail offices were built. !.

The Network Rail offices were built on top of an old carriage siding. It may have extended under the Blackfriars to Elephant line but I don't think it joined back on to the Charing Cross line. We are talking 30+ years ago though, so my memory may be playing tricks.

 

[swt_passenger]

The Network Rail offices were built on top of an old carriage siding. It may have extended under the Blackfriars to Elephant line but I don't think it joined back on to the Charing Cross line. We are talking 30+ years ago though, so my memory may be playing tricks.

Southwark (EMU) sidings from 1969. Formerly the LCDR's Southwark 'Continental Freight Depot' and on the same site Ewer St loco stabling depot.

There's an article about this location on the Kent Rail website; seems the steel bridge that extends across Great Suffolk St and then takes a route under the Blackfriars/Elephant lines was only ever the road access, it slopes down as it is crossing and then round to the north to join Dolmen St at road level: https://goo.gl/maps/ltwgm

Apologies for the diversion from the main London Bridge topic, but I thought others might be interested:

http://kentrail.org.uk/ewer_street_southwark_depot.htm

 

[RichardN]

There is something called constraint theory, which states that it only makes sense to fix problems which are capacity constraints, since these set the limit to your overall capacity. This view of the world sees spending on a burrowing junction as a waste of money. I don't entirely agree as there is a lot to be said for improving "perceived" performance, providing it can be done cheaply enough. A delay while a set waits in platform will be less apparent to the public than a delay waiting for the points at the junction. To achieve this you'd need two platform faces northbound at Blackfriars and grade separation at the junction, i.e. probably not very cheap.

The flat crossing at Blackfriars is less of a problem than it would be because an eight car train travelling South via Elephant and Castle doesn't block a following London Bridge bound service. Normally the pattern will be E&C, LB, LB, E&C, LB, LB etc. So a southbound train can wait for a gap for up to 5 minutes without any knock on effects to following services.

 

[Peter Sarf]

I should add that the quadrupling of tracks through Borough market (to the west of London Bridge) must be a huge shot in the arm for capacity.
--- old post above --- --- new post below ---

There is something called constraint theory, which states that it only makes sense to fix problems which are capacity constraints, since these set the limit to your overall capacity. This view of the world sees spending on a burrowing junction as a waste of money. I don't entirely agree as there is a lot to be said for improving "perceived" performance, providing it can be done cheaply enough. A delay while a set waits in platform will be less apparent to the public than a delay waiting for the points at the junction. To achieve this you'd need two platform faces northbound at Blackfriars and grade separation at the junction, i.e. probably not very cheap.

The flat crossing at Blackfriars is less of a problem than it would be because an eight car train travelling South via Elephant and Castle doesn't block a following London Bridge bound service. Normally the pattern will be E&C, LB, LB, E&C, LB, LB etc. So a southbound train can wait for a gap for up to 5 minutes without any knock on effects to following services.

I can see that forward thinking is constrained by that !.

Thanks for the point regarding the flat crossing. Am I right in understanding that an 8 car Southbound to Elephant and Castle will effectively be held at the junction until there is a corresponding Northbound 8 car coming from Elephant and Castle. This is possible because other 12-car Southbound services towards London Bridge can overtake it just before the junction as there is a long enough loop ?.

The above only goes wrong if reality kicks in and two E&C bound trains come out of the core together and several late running 12-car trains from London bridge are going North !. Well we know the core is going to be fragile - that is what one gets when cunningly getting every last drop of capacity out of something. Roll on Crossrail 3, 4 and 5 .

 

[RichardN]

I should add that the quadrupling of tracks through Borough market (to the west of London Bridge) must be a huge shot in the arm for capacity.
--- old post above --- --- new post below ---


I can see that forward thinking is constrained by that !.

Thanks for the point regarding the flat crossing. Am I right in understanding that an 8 car Southbound to Elephant and Castle will effectively be held at the junction until there is a corresponding Northbound 8 car coming from Elephant and Castle. This is possible because other 12-car Southbound services towards London Bridge can overtake it just before the junction as there is a long enough loop ?.

The above only goes wrong if reality kicks in and two E&C bound trains come out of the core together and several late running 12-car trains from London bridge are going North !. Well we know the core is going to be fragile - that is what one gets when cunningly getting every last drop of capacity out of something. Roll on Crossrail 3, 4 and 5 .

The line for London Bridge will diverge from the Line for E&C with room for an 8 coach train between the point of divergence and the crossing, so the E&C bound train can wait there for a gap without blocking London Bridge bound trains.

 

[hwl]

I should add that the quadrupling of tracks through Borough market (to the west of London Bridge) must be a huge shot in the arm for capacity.
--- old post above --- --- new post below ---

Thanks for the point regarding the flat crossing. Am I right in understanding that an 8 car Southbound to Elephant and Castle will effectively be held at the junction until there is a corresponding Northbound 8 car coming from Elephant and Castle. This is possible because other 12-car Southbound services towards London Bridge can overtake it just before the junction as there is a long enough loop ?.

The above only goes wrong if reality kicks in and two E&C bound trains come out of the core together and several late running 12-car trains from London bridge are going North !. Well we know the core is going to be fragile - that is what one gets when cunningly getting every last drop of capacity out of something. Roll on Crossrail 3, 4 and 5 .

Everything there will be controlled by ATO so you can slow or speed up trains as required to create a bigger gap for the southbound E&C services. Block lengths will also very short.

24tph is one train every 2m30s on average but I suspect the spacing at the junction won't be like that and it might make sense to space 2 consecutive services from London Bridge at slightly longer say 3 minutes as that works better for the platforms at LBG and the BML fasts etc.

At 30mph a 12 car train will pass in less than 20 seconds so you should be able to get a southbound E&C service between 2 consecutive Northbound services from LBG or 2 Southbound services in the "gap" in services from LBG.

 

[IanKR]

Will the new viaduct over Borough Market (south of the existing tracks) carry *both* (up & down) Charing Cross lines? It doesn't look wide enough!

 

[neilm]

Will the new viaduct over Borough Market (south of the existing tracks) carry *both* (up & down) Charing Cross lines? It doesn't look wide enough!

It will and is

 

[IanKR]

That's a very old diagram; whilst it shows the principles of the changes and correctly depicts the grade separation, the new layout itself is different to that shown.

Is there a newer one available?
--- old post above --- --- new post below ---

It will and is

Must be an optical illusion, or summat.

 

[Bald Rick]

Is there a newer one available?
--- old post above --- --- new post below ---


Must be an optical illusion, or summat.

There's not a newer version of that map (which is over 5 years old) but there is a better depiction of the layout in the same presentation.

The viaduct is more than wide enough, look at it on google maps, or stand underneath it inside Boro Market, and you'll see it is wider than the existing viaduct.

 

[IanKR]

The viaduct is more than wide enough, look at it on google maps, or stand underneath it inside Boro Market, and you'll see it is wider than the existing viaduct.

I'm sure it is(!). I've only seen it from the train when passing the Charing Cross end of it where it merges.

 

[swt_passenger]

I'm sure it is(!). I've only seen it from the train when passing the Charing Cross end of it where it merges.

There is to be a slight widening of the viaduct on the north side at that end as well, which should help improve what seems to be a bit of a pinch point at the moment.

 

[IanKR]

There is to be a slight widening of the viaduct on the north side at that end as well, which should help improve what seems to be a bit of a pinch point at the moment.

It looks like the alignment of what will be the TL tracks (currently LBG-WAE-CHX) in that area will change - heading slightly further northwards than at present towards Blackfriars. This is what I'm guessing from the extension 'viaduct'(?) on the north side of the tracks, within the triangle and behind the Market Porter pub? It looks like the CST-WAE spur will survive, but that track will need to be realigned at that junction to accommodate?

 

[swt_passenger]

Yes, there'll be quite a significant slew. I found an aerial view taken from the Shard that shows the new 'shape' well:
https://c4.staticflickr.com/4/3717/9372293202_e6ca242e05_b.jpg

 

[MikeWh]

It looks like the CST-WAE spur will survive, but that track will need to be realigned at that junction to accommodate?

I'm not convinced it will survive as a link between CST and WAE, certainly not for normal running. You'd need to cross the Thameslink lines for that.

 

[Peter Sarf]

I'm not convinced it will survive as a link between CST and WAE, certainly not for normal running. You'd need to cross the Thameslink lines for that.

I think it was mainly used for empty stock movements to feed Cannon Street from the sidings that were up towards Blackfriars but I am not sure what happens nowadays.

 

[carriageline]

I believe two trains a day use it from Blackfriars, but that's from my casual observing so may be incorrect!

 

[NSEFAN]

Metropolitan curve is indeed used for stock movements but also sees some late-night passenger workings. Here's some examples from RTT.

 

[Bald Rick]

I believe two trains a day use it from Blackfriars, but that's from my casual observing so may be incorrect!

It's about 5 each way a day. Until next August.

 

[Philip C]

Metropolitan curve is indeed used for stock movements but also sees some late-night passenger workings. Here's some examples from RTT.

Since the trackwork undertaken at Easter(?) it is no longer possible to run from Cannon Street to Waterloo (East) except by wrong-line running as far as the throat of Charing X..

The reason that those late night trains run via Cannon Street is, probably, to enable them to call at London Bridge. If this is the case it seems a little odd, in that every train from Charing X currently passes through Platform 4 at London Bridge and this, being the opposite side of island platform from Platform 3 (which is in normal use), appears entirely serviceable though not used. My suspicion is that the diversion through Cannon Street is thus merely to prevent pressure for more frequent use of Platform 4 were it to be returned to limited use.

 

[david737]

The reason that those late night trains run via Cannon Street is, probably, to enable them to call at London Bridge. If this is the case it seems a little odd, in that every train from Charing X currently passes through Platform 4 at London Bridge and this, being the opposite side of island platform from Platform 3 (which is in normal use), appears entirely serviceable though not used. My suspicion is that the diversion through Cannon Street is thus merely to prevent pressure for more frequent use of Platform 4 were it to be returned to limited use.

The reason the late night trains run via Cannon Street is due to a possession of the Dn Charing X & Up Cannon St. lines that goes on at 2355 each weekday night. Trains could call at plat 4 London Bridge but would need to be manually dispatched since all the CD & RA equipment has been removed.