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Post by Hutch on Dec 11, 2017 13:38:46 GMT
Surreal. Wonder what they do with all the removed segments; presumably there isnt much of a need for spares! Would they have a use in station reconstruction projects I wonder. I could imagine that the scrap is quite valuable as it is pre-nuclear in age ( Low-background steel). Since the birth of The Bomb and nuclear testing in the 1950's and 60's all steel produced to day has traces of radio-nuclides , but for some very sensitive instruments one must use pre-nuclear steel which is quite rare and thus valuable. Scuttled warships at Scapa Flow were a source. |
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vato
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Post by vato on Dec 11, 2017 16:54:27 GMT
Tech question What is a step plate junction? Whilst this has already been answered, it becomes clearer once you understand that this is a general tunnelling term, rather than a railway term. So, not the kind of junction I was originally expecting (a point or turnout), but rather a junction of tunnels, which uses flat end (step) sections when the diameter changes. |
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Post by goldenarrow on Dec 11, 2017 20:57:16 GMT
Has anyone got an update on how this is all progressing, please? The next major phase of works is scheduled to take place during the ten day closure of the Kennington Loop (link to IanVisits) over the christmas period that will see the new tunnels linked up to the existing Northern line. Presentley, the Kennington Loop pasess through the step plate junction on the tray of the existing tunnel rings. If the connection is to involve track/point work then the lowering of the loop is inevitable to line it up with the new pieces of railway. Excavation of the station box at Battersea is well underway with the capacious nature of the station already making itself apparent. It starts with an access shaft that is dug down to the level which for the NLE is about 25m underneath Kennington Green. A tunnel of a wider diameter is then mined (not using a TBM) towards the Kennington Loop. As the new tunnel tapers towards the existing the tunnel the diameter of the tunnel dug gets larger in increments forming the basis of the step plate junction made possible by shotcrete linings (used at Tottenham Court Rd aswell) being quick to apply and much more flexible than conventional tunnel segments. During this time there is still a complex web of scaffolding, brace and support structures in place around the existing tunnel as the new chamber is embiggened before finally being lined with the spheroidal graphite iron rings that now line the chamber. Channel 5's Inside the Tube: Going Underground visited the works whilst the chamber was still being enlarged around the locked in Kennington Loop.In the Kennington area it's just a conspicuous green shed that covers one of the access shafts whilst at Battersea there's a whole medley of works although I cannot recall weather these can be seen from a train around the Battersea Park area. |
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Ben
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Post by Ben on Dec 11, 2017 22:19:31 GMT
Surreal. Wonder what they do with all the removed segments; presumably there isnt much of a need for spares! Would they have a use in station reconstruction projects I wonder. I could imagine that the scrap is quite valuable as it is pre-nuclear in age ( Low-background steel). Since the birth of The Bomb and nuclear testing in the 1950's and 60's all steel produced to day has traces of radio-nuclides , but for some very sensitive instruments one must use pre-nuclear steel which is quite rare and thus valuable. Scuttled warships at Scapa Flow were a source. Yes absolutely! Its so funny you said that actually, as I made a very similar comment on Facebook w.r.t the scrapping of the Island Lines 38ts; didn't think to make the connexion. Medical equipment, and measuring/calibration equipment are IIRC two examples. |
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Post by Deleted on Dec 19, 2017 1:12:28 GMT
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Post by banana99 on Dec 19, 2017 10:22:15 GMT
Incredible engineering. Wow.
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Post by rsdworker on Dec 19, 2017 18:02:57 GMT
i have question - what stations will look like?
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Post by Alight on Jan 4, 2018 17:42:06 GMT
Has anyone been able to spot it from riding the Kennington Loop yet?
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Chris M
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Post by Chris M on Jan 4, 2018 19:34:53 GMT
Given the pictures that show the top half of the loop tunnel removed in at least one new step plate junction chamber, I would ask that every single driver, and every single awake passenger, who has been around the loop since this was done and failed to spot it have their eyes tested before they are next allowed to operate machinery.
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Post by toby on Jan 4, 2018 20:03:21 GMT
Is it lit in passenger running time?
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Post by MoreToJack on Jan 4, 2018 22:22:16 GMT
Is it lit in passenger running time? For now, yes. |
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Post by Alight on Jan 6, 2018 15:03:33 GMT
Given the pictures that show the top half of the loop tunnel removed in at least one new step plate junction chamber, I would ask that every single driver, and every single awake passenger, who has been around the loop since this was done and failed to spot it have their eyes tested before they are next allowed to operate machinery. Sorry, I meant to ask - has anyone been able to photograph it from riding on the loop? |
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Post by jukes on Jan 6, 2018 16:44:17 GMT
Incredible engineering. Wow. Its called a step plate junction and the same thing was done on the Victoria Line at Finsbury Park, Highbury & Islington etc., during construction of cross-platform interchanges during 1965-6. |
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Post by londonstuff on Jan 6, 2018 19:07:07 GMT
I think what they've done - tunnelling around the existing loop - is nothing short of amazing and seeing various pics of the iron rings being slowly removed has been really interesting. These are photos of the two junctions since the track was lowered. *Obviously the person taking the photo wasn't driving at the time and was authorised to be there  |
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Post by Deleted on Jan 6, 2018 19:09:18 GMT
Didnt they do this with the T5 extension or was it cut and cover i dont seem to remember
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North End
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Post by North End on Jan 6, 2018 21:48:08 GMT
Didnt they do this with the T5 extension or was it cut and cover i dont seem to remember The Piccex Junction (awful name, which unfortunately has stuck) was done with a box being excavated, hence the need for a lengthy closure. I think I remember this being due the ground being water bearing. Same applies to the Northern Line's diversion tunnel at London Bridge. The north end of this was done by means of the tunnel being back filled and the new tunnel being excavated through it. This was due to the proximity of the river. Only a few rings of the old tunnel remain north of the original southbound platform. Same applies to the old Embankment loop. In this case its former existence is hard to spot from today's tunnels, although there are tell-tale signs. |
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Post by John Tuthill on Jan 6, 2018 21:58:17 GMT
Didnt they do this with the T5 extension or was it cut and cover i dont seem to remember The Piccex Junction (awful name, which unfortunately has stuck) was done with a box being excavated, hence the need for a lengthy closure. I think I remember this being due the ground being water bearing. Same applies to the Northern Line's diversion tunnel at London Bridge. The north end of this was done by means of the tunnel being back filled and the new tunnel being excavated through it. This was due to the proximity of the river. Only a few rings of the old tunnel remain north of the original southbound platform. Same applies to the old Embankment loop. In this case its former existence is hard to spot from today's tunnels, although there are tell-tale signs. Which explains why the northbound platform is on a curve and the southbound is straight. |
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Post by londonstuff on Jan 7, 2018 9:24:03 GMT
Here’s another with a bit more detail.  |
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Post by Deep Level on Jan 7, 2018 11:38:55 GMT
What's the need for the shutters?
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Chris M
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Post by Chris M on Jan 7, 2018 11:51:19 GMT
I imagine it will be to fully segregate the worksite and reduce the impact of air currents from passing trains.
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Post by trt on Jan 7, 2018 12:50:40 GMT
What's the need for the shutters? Doused in holy water and daubed with religious symbols. They're a ghost containment feature. |
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North End
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Post by North End on Jan 8, 2018 0:46:09 GMT
I imagine it will be to fully segregate the worksite and reduce the impact of air currents from passing trains. Indeed. It also acts as a fire barrier, as well as stopping nosy staff walking into the construction site. |
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Post by superteacher on Jan 9, 2018 16:44:56 GMT
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Post by holborncentral on Jan 12, 2018 15:51:46 GMT
What's the need for the shutters? Doused in holy water and daubed with religious symbols. They're a ghost containment feature. Will that keep the Kennington Loop ghost out of the NLE? Come to think of it, has anyone ever seen the ghost? |
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rincew1nd
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Post by rincew1nd on Jan 12, 2018 19:15:01 GMT
Doused in holy water and daubed with religious symbols. They're a ghost containment feature. Will that keep the Kennington Loop ghost out of the NLE? Come to think of it, has anyone ever seen the ghost? Depends if they're symbols from the same religion as the ghost. |
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Post by holborncentral on Jan 12, 2018 19:18:05 GMT
Will that keep the Kennington Loop ghost out of the NLE? Come to think of it, has anyone ever seen the ghost? Depends if they're symbols from the same religion as the ghost. True, but do we know what religion the ghost is, if any? |
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Post by Deep Level on Jan 12, 2018 19:31:59 GMT
Doused in holy water and daubed with religious symbols. They're a ghost containment feature. Will that keep the Kennington Loop ghost out of the NLE? Come to think of it, has anyone ever seen the ghost? Am I the only one seeing the ghost in the photo clearly on the loop?  |
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Ben
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Post by Ben on Jan 12, 2018 20:19:22 GMT
Tip of current rail painted green - interesting.
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rincew1nd
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Post by rincew1nd on Jan 12, 2018 20:43:24 GMT
Looks like both poz and neg but only on the loop not the extension.
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Post by ted672 on Jan 12, 2018 23:44:47 GMT
Does anyone know how far the track extends beyond the shutters?
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