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Post by Nortube on Mar 21, 2013 17:54:52 GMT
City & South London Railway changesThe C&SLRly originally ran between Stockwell and King William Street, with a depot above ground at Stockwell. The line was later extended south to Clapham Common and diverted just north of Borough to run to Euston. The original City & South London Railway station tunnels were about 200 feet long and constructed of brick. In preparation for joining up with the Charing Cross branch at Kennington and Camden Town, the extension to Morden and the new full size rolling stock, the station tunnels were extended to around 350 feet, using standard cast iron linings and the running tunnels were widened. Evidence of the brickwork can still be seen in places. On many platforms, it is easy to see where the station tunnel has been lengthened because the newer station tunnels were slightly bigger. Where they were extended varied from station to station. Some platforms were extended northwards, some southwards, and some extended at both ends. Because most platforms originally had a rising gradient on approach, were level in the platform, and had a falling gradient on departure, where the platform has been lengthened can often be seen by the position of the gradient and level on the gradients section of the Driving Techniques diagrams. E.g., if a platform is level with a fall at the front third of the platform (Old St SB), then that platform was probably extended to the front. If a platform is level with a fall at the rear third of the platform (Kings Cross SB), then that platform was probably extended to the rear. This is only a rough guide and doesn't always work that way. At Angel, all of the platform is level because although the platform was extended south, it was extended over where the scissors crossover used to be and so that area was level as well. At Clapham North northbound, where the platforms were extended northwards, even though there is a slight fall in the platform at the north end, a 1 in 30 fall was created for a short distance immediately departing the platform. As a consequence, the tunnel mouth is larger to accommodate the extra height of the train at that point and the tunnel is funnel shaped. This gradient within the platform is why a train may roll when the brakes are released in the platform. I have included some diagrams in the following posts. They are basic and not to scale, but they should give you an idea of what the changes were. Elephant & CastleWhen Elephant & Castle station opened in 1890, the NB platform was on the opposite side to today, train doors opening on the right. Entrance / exit to both platforms was from the south end of the platforms. North of the station, a siding ran between the SB platform and the NB running line, almost like a long emergency crossover. Indeed, it could have been used as a crossover between the two running lines if required. When the platforms were lengthened and the tunnels widened in the 1920s, changes were also made to the NB platform layout to give easy access to the Bakerloo line from the NB platform. The diagram shows the changes. Both platform tunnels were extended south. The NB track was realigned so that the platform was on the left. This meant that a step-plate type tunnel had to be built to allow the track to curve to its new position. New exits were provided at the south end of the platforms to replace the original ones that the platform lengthening had cut into. Exits were also provided at the north end of the platforms to the Bakerloo line. Until this time, the Bakerloo and Northern line each had their own totally separate stations, with separate street entrances. At the same time, the SB running tunnel was realigned into part of the siding to take away some of the tight curve at the entrance to the platform. The speed limit over the curve was originally 12mph. Today it is 20mph.
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Post by Nortube on Mar 21, 2013 17:56:06 GMT
KenningtonThe C&SLRly platforms (now the Bank branch) are on two different levels. When the station opened in 1990, the NB platform was on the opposite side to today, train doors opening on the right. When the Charing Cross branch was extended from Strand (now CX) to Kennington, the NB platform at Kennington was altered to give cross-platform interchange between the two branches. This gave the layout as shown in the diagram, where the track actually curves slightly within the beginning of the south end of the platform and, like the entrance at Elephant & Castle curves back to the original layout in the wide space north of the platform.
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Post by Nortube on Mar 21, 2013 19:17:32 GMT
Stockwell 1Stockwell was the original terminus, with an island platform. The platform was where the emergency crossover is today. Exit from the platform was from the end of the platform. The original exit can be seen today as the passageway to the left just as the train departs Stockwell NB. The C&SLRly depot was above ground located where Stockwell Gardens is today. There was also a generating station which provided power for the line. The depot and generating station have long gone, but a little of the site still remains, used for the Stockwell substation. The simplified diagrams below show some of the main changes to Stockwell station over the years. The first diagram shows how it was at the opening in 1890. When the line was extended to Clapham Common in 1900, stairs were added from the end of the platform as the original passageway was no longer accessible. The second diagram shows Stockwell in 1924. Instead of extending the original platforms, new platforms were built to the south of the existing island platform. Exit was from the north end of the platforms. By 1975, the track to the depot and siding had already been removed. An emergency crossover was installed on the site of the island platform. The long siding tunnel is still there, but is blocked off by an IMR at the north end. When travelling south, if you look back to your left as the train enters the double track section, you can see the depot tunnel. If you look ahead to your left, in the open rectangle, you can just see the remaining short stub of the other end of the siding. The IMR is behind it. The tiles from the original platform area can still be seen on the ceiling of the crossover tunnel. Stockwell 1890 and 1923 Stockwell 1924 and today
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Post by Nortube on Mar 23, 2013 1:20:57 GMT
Clapham CommonClapham Common was the southern terminus of the C&SLRly after is was extended south of Stockwell in 1900. A pit siding was provided so that locos could be serviced and the ends of the running tunnels each became 450 feet long sidings where trains were stabled overnight. In preparation for the new rolling stock and the extension to Morden, the station tunnel was lengthened northwards over the existing crossover, the running tunnels and the entrance to the pit siding. This work also cut into the pit siding tunnel and the parallel part of this was filled in, just leaving a solitary stub in isolation. When the new crossover was installed at Stockwell in the seventies, the crossover at Clapham Common was taken out of service and the rails lifted.
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Post by Nortube on Mar 24, 2013 20:44:55 GMT
AngelAngel was a temporary terminus when the C&SLRly was extended to Euston. It had a long siding for stabling trains that was accessible from either platform. When the tunnels were widened and the platforms lengthened in 1924, the platform was extended over the site of the old scissors crossover and access to the siding was from the NB platform. The siding was closed in 1959. Because of severe overcrowding on the island platform, the NB running line was diverted to a new platform in 1992 and the old SB platform filled in, leaving an extra wide SB platform.
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Post by Nortube on Mar 26, 2013 0:59:29 GMT
Stockwell 2Tied in with the changes at Stockwell, the diagram below (taken from a circular) shows the layout during single line working under compressed air. Single line working was put into operation from 22 October 1923. The NB / SB tracks were closed as required. This diagram shows single line running on the NB line between Stockwell and the crossover at Portland Place. When single line running was on the SB line, the other crossover at Portland Place was used. There was also a crossover further north at South Island Place. Diagram 1 shows the Signalling Diagram, diagram 2 shows the Locking List 1 2
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Post by Nortube on Mar 27, 2013 23:15:15 GMT
London BridgeWhen the C&SLRly was diverted at Borough to run as far as Euston, London Bridge was the next station. Although the C&SLRly tunnels are directly above the Northern line platforms at London Bridge, there was never a station there on the C&SLRly. Presumably it wasn't thought worth it as few passengers would want to alight there and any passengers arriving by main line at London Bridge would not want to go to the effort of getting the 'tube' just to get to the other side of the bridge. The station was built to the (then) standard platform length and had a 144 feet long siding at the south. The siding led off from the emergency crossover and was only directly accessible from the NB platform. 1n 1916, one train entered service from the siding at the start of the morning rush hour, and one train stabled there in the evening. The platforms were later extended northwards, to the standard 350 feet length and the running tunnels widened. The siding was closed and an emergency crossover was built in its place to allow N-S and S-N reversing at London Bridge. Because NB and SB running is reversed between Borough and Bank stations inclusive, this meant that London Bridge was the only station on the Northern line that permanently had an emergency crossover south of the station (not including Totteridge, which was hand-worked and could not be easily used.) In 1995, as part of the work for the arrival of the Jubilee line at London Bridge and the improvement of passenger flow at the station (an extremely busy tube station in the morning peak), the SB line was diverted to a new platform. The old SB platform and track area became a circulating area between the NB and SB platforms, with access to the Jubilee line and a new exit at Borough High Street that by-passed the main line station. Because of construction limitations at the north end of the diversion (which I believe were due to the proximity of the old London Bridge (river bridge) foundations), it was impossible to build a step-plate junction which is the usual practice. Instead, the line had to be closed, the old tunnel temporarily filled in at the diversion, and the new tunnel dug though that. A step-plate junction was used at the south end. See a different thread [ here ] for some photos of the step-plate edit 300313-22:!2 - diagram amended to show approximate position of wider tunnels and platform exits and what I think is the correct layout for the siding. Paragraph 2 has also been amended accordingly
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Ben
Box Boy
Posts: 65
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Post by Ben on Mar 28, 2013 0:29:14 GMT
Presumably it would be possible to reinstate a crossover at the south if a step plate were used for the diversion, should there ever be an inclination? Or were the bit of Southbound running tunnel and the crossover tunnel filled up?
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Post by Nortube on Mar 28, 2013 0:59:51 GMT
The exit from the platforms at London Bridge was off the south end. As you walked off the end of the platforms, you went up stairs / turned left and effectively went over the crossover tunnel. When the SB platform and platform track became the circulating area, the space that used to contain the emergency crossover was used as various equipment rooms. Steps from the south end of the circulating area led up to a circulating area above the rooms. escalators from the circulating area led off to the Borough High St exit.
Its possible that an emergency crossover could have been built further south of the step-plate, but I'm not sure if the tracks are level (I suspect not). I think there was an option for the crossover to be installed somewhere, but it was decided it wasn't worth it as there was the crossover at Moorgate. The London Bridge crossover wasn't used much. I think I only reversed there twice.
edit 280313-22:05 - the first paragraph has been revised
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Ben
Box Boy
Posts: 65
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Post by Ben on Mar 28, 2013 1:33:01 GMT
Ah righto, thanks for that! Not my neck of the woods.
If this future operations paradigm is to be made possible with 24hour bi-di running, at some point it would seem inevitable that more crossovers will need plumbing in!
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Post by dave1 on Mar 28, 2013 9:47:20 GMT
Re London Bridge was the IMR not in the old siding?
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Post by Nortube on Mar 28, 2013 10:52:48 GMT
I'm not sure about the IMR, but it's quite possible it was situated there, it's a logical place to put it. The siding was no longer wanted when the tunnels were widened, and the north part was cut through by the emergency crossover. However some of the south end of the still remains and has two rooms that contain electrical equipment / relays. As we're at London Bridge ; following on from a previous post somewhere about ventilation shafts etc., If you stood at the south end of the NB platform at London Bridge and looked left, you could see a large grill in the tunnel wall where the crossover was. Behind this was a tunnel which led to the bottom of one of the lift shafts. Like many similar tunnels, this tunnel was built for access when the line was being built. It is one from the original C&SLRly station on Borough High St / London Bridge St. The lift shaft first being used as access to the surface, then as a lift shaft then, after after escalators replaced the lifts, for ventilation. I can't remember what that area looks like now since all the changes. I imagine the tunnel is still used for ventilation, but I don't know if it can still be seen. edit 280313-21:53 - the first paragraph has been revised.
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Post by Nortube on Mar 28, 2013 11:28:00 GMT
Ah righto, thanks for that! Not my neck of the woods. If this future operations paradigm is to be made possible with 24hour bi-di running, at some point it would seem inevitable that more crossovers will need plumbing in! I think it's always regretted after something is removed. The more reversing points the better for flexibility of service. Ideally, scissors crossovers would give the most flexibility in bi-di running, but even the existing emergency crossovers will be very useful, especially when running the "wrong way" where no shunting is involved. E.g. running south along the NB bank branch to Moorgate then continuing south from there along the SB track. I never saw the point of doing away with Totteridge crossover. There are many times when the Barnet branch has had to be suspended between Finchley Central and High Barnet because of problems at High Barnet. Some suspensions may be small, others a long time. At some of these times, trains may have been stuck between stations. The crossover at Totteridge was never used because it would have been too much trouble to set everything in motion as the crossover was hand-worked. However, if it was a normal signalled crossover, then it would just be a case of. "Change ends in the platform driver" and that was it. It seems very backward not to have included Totteridge crossover in the upgrade works. Even though it may be possible to bi-di trains on the branch in future, if High Barnet is unavailable for whatever reason, trains would have to travel wrong road as far as the next physical NB-SB connection at the emergency crossover at East Finchley to get back to right road running. This effectively means only one train between East Finchley and Totteridge (or whatever) and the consequent restrictions to the rest of the branch from Camden Town. Not even worth thinking about doing. There was talk about the crossover at Clapham Common being reinstalled under the upgrade works. I don't know if this will happen, or was just wishful thinking. There's no physical reason why it can't be done as there is space for a single or scissors crossover. Likewise Stockwell could be converted to a scissors crossover if required. I don't know if there would be any advantage having two sets of crossovers close together. I don't think it would be possible to reinstate the crossover south of Moorgate (not enough space), although it might be possible to put the one back in south of Archway. Euston City SB would be a convenient place to send SB trains south over the NB line via Euston loop. It's already possible physically, it would just need resignalling.
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Post by hellocontrol on Mar 28, 2013 14:51:37 GMT
Re London Bridge was the IMR not in the old siding? The IMR was in a tunnel which I am sure was the old siding tunnel it could be seen when the lights were on from the south end of the NB platform ( 12 shaft V frame ).
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Post by hellocontrol on Mar 28, 2013 14:56:27 GMT
Ah righto, thanks for that! Not my neck of the woods. If this future operations paradigm is to be made possible with 24hour bi-di running, at some point it would seem inevitable that more crossovers will need plumbing in! I never saw the point of doing away with Totteridge crossover. There are many times when the Barnet branch has had to be suspended between Finchley Central and High Barnet because of problems at High Barnet. Some suspensions may be small, others a long time. At some of these times, trains may have been stuck between stations. The crossover at Totteridge was never used because it would have been too much trouble to set everything in motion as the crossover was hand-worked. However, if it was a normal signalled crossover, then it would just be a case of. "Change ends in the platform driver" and that was it. It seems very backward not to have included Totteridge crossover in the upgrade works. Even though it may be possible to bi-di trains on the branch in future, if High Barnet is unavailable for whatever reason, trains would have to travel wrong road as far as the next physical NB-SB connection at the emergency crossover at East Finchley to get back to right road running. This effectively means only one train between East Finchley and Totteridge (or whatever) and the consequent restrictions to the rest of the branch from Camden Town. Not even worth thinking about doing. There was talk about the crossover at Clapham Common being reinstalled under the upgrade works. I don't know if this will happen, or was just wishful thinking. There's no physical reason why it can't be done as there is space for a single or scissors crossover. Likewise Stockwell could be converted to a scissors crossover if required. I don't know if there would be any advantage having two sets of crossovers close together. I don't think it would be possible to reinstate the crossover south of Moorgate (not enough space), although it might be possible to put the one back in south of Archway. Euston City SB would be a convenient place to send SB trains south over the NB line via Euston loop. It's already possible physically, it would just need resignalling. The cross over at Totteridge was not in the upgrade although I understand they asked for it to be included but it was declined. At High Barnet I think there are some unused sidings again when asked it was declined to include them. The left hand not taliking to the right. There was talk of including Clapham Common and re-instating the cross over, 1995 TS can display Clapham Common as a destination.
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