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« Reply #2520 on: December 23, 2013, 17:16:00 » |
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Todays's unexpected news is that the track has been lifted through P10 again. The eastern (newer) section still has the sleepers still in place, the older section under the transfer deck and towards the west end has been removed complete with the sleepers...
Weird. Seemed only a few days ago that they'd aligned the eastern section properly...
Paul
I wonder if one of them has dropped a USB stick full of bitcoins in the ballast ...
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stuving
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« Reply #2521 on: December 23, 2013, 19:12:59 » |
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Todays's unexpected news is that the track has been lifted through P10 again. The eastern (newer) section still has the sleepers still in place, the older section under the transfer deck and towards the west end has been removed complete with the sleepers...
More seriously, doesn't this track need to be raised to match the new platform height? The amount of lift varies, but IIRC▸ it's 150mm in some places. Is that too much to be done by just adding ballast - could it end up to deep? The eastern part of the track and bed is new, but the western part has been in situ since it was in use with the old platform height.
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Jonty
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« Reply #2522 on: December 23, 2013, 20:16:03 » |
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Regarding the drainage, I think the bottom of the steps will still be higher than the bottom end of Greyfriars Road, so presumably it will drain in that westerly direction...?
In the interminable time that RBC‡ spent in preparing the dug-out Station Hill area, they appeared to put a good number of chunky looking drains in...
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ellendune
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« Reply #2523 on: December 23, 2013, 20:22:12 » |
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Regarding the drainage, I think the bottom of the steps will still be higher than the bottom end of Greyfriars Road, so presumably it will drain in that westerly direction...?
In the interminable time that RBC‡ spent in preparing the dug-out Station Hill area, they appeared to put a good number of chunky looking drains in...
I assume that will also be the ground floor level for the new Station Hill development.
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ironstone11
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« Reply #2524 on: December 23, 2013, 21:24:23 » |
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Regarding the drainage, I think the bottom of the steps will still be higher than the bottom end of Greyfriars Road, so presumably it will drain in that westerly direction...?
Difficult to be sure. Looking at the pictures of the construction of the existing ramp/steps I got the impression that the path may be going uphill in a westerly direction from the mouth of the subway. Those who use the subway may be able to confirm.
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paul7575
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« Reply #2525 on: December 24, 2013, 20:19:19 » |
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Todays's unexpected news is that the track has been lifted through P10 again. The eastern (newer) section still has the sleepers still in place, the older section under the transfer deck and towards the west end has been removed complete with the sleepers...
More seriously, doesn't this track need to be raised to match the new platform height? The amount of lift varies, but IIRC▸ it's 150mm in some places. Is that too much to be done by just adding ballast - could it end up to deep? The eastern part of the track and bed is new, but the western part has been in situ since it was in use with the old platform height. The plot thickens... Just had a look at the 2014 Engineering Access statement (although it's now overtaken by the 'confirmed period possession plan') and it refers to the track through Platform 10 being relaid later on in the year, about April or May. Now if that was the original plan, and given that the P10 completion is now assumed to have been brought forward to February, (as per the last 'station news', then this would be the obvious time to relay it properly. A further closure after re-opening would look like bad planning... No idea about the maximum lift they can achieve just by using more ballast, but at a guess, might they be replacing the underlay material, is it 'Terex' or something? Or working on the drainage? Whatever the reason I suppose it will all become clear in due course, it might even be reinstalled in only a few days time... Paul
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ellendune
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« Reply #2526 on: December 24, 2013, 22:28:03 » |
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... but at a guess, might they be replacing the underlay material, is it 'Terex' or something?
I think you mean Terram TM‡ (other makes of geotextile products are available)
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paul7575
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« Reply #2527 on: December 27, 2013, 15:39:09 » |
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... but at a guess, might they be replacing the underlay material, is it 'Terex' or something?
I think you mean Terram TM‡ (other makes of geotextile products are available) Yes, probably. That's the sort of word you'd get if you memorised Ter(ramgeot)ex wrongly... Paul
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paul7575
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« Reply #2528 on: December 27, 2013, 15:52:01 » |
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Report at lunchtime today.
Station operating with P4/5 and P12-15 in use only.
Majority of work taking place on P7 and P9, with the polystyrene bridges in place for level access from P7 across P8/9 as far as P10/11.
A couple of photos below, the first one suggests that by next week the whole of the P9 edge coping might be complete. You can see that they are making progress in a few different areas, directly under the transfer deck steel sections are being bolted to the subway girder bridge to carry the new slabs, followed by a section of edging that looks complete. Then there's a gap where machines are operating demolishing existing stuff, and then a fairly long section complete at the far London end.
Next to P6 a significant length of the temporary P7 had already been removed completely, you can see in the photo they are working in the vicinity of the remaining 'bridge' over to P6, everything east of there including the other access 'bridge' had already been removed at around 1230. The deck boards had been removed over the full length, it seemed they were left with the basic scaffold components to remove, so I don't see that taking too long at all now.
The length of P7 alongside P3 looked pretty clear of materials, electrical installations were ongoing, and I'd anticipate that they'll probably arrange things so that the trains will stop at the far west end, as there is still loads of work to be done under the new 'ski jump' roof in the middle of the platform.
Hope this is of interest.
Paul
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stuving
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« Reply #2529 on: December 27, 2013, 18:32:44 » |
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Next to P6 a significant length of the temporary P7 had already been removed completely, you can see in the photo they are working in the vicinity of the remaining 'bridge' over to P6, everything east of there including the other access 'bridge' had already been removed at around 1230. The deck boards had been removed over the full length, it seemed they were left with the basic scaffold components to remove, so I don't see that taking too long at all now.
This picture is from lunchtime, and later on that second bridge from P6 was gone too. As you can see, the planking was only taken off when they were ready to dismantle the scaffolding. That would give them something to walk on to carry all the bits away.
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stuving
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« Reply #2530 on: December 27, 2013, 18:47:00 » |
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Look - they're breeding! So, for all that I still think this look a bit of a lash-up, these things are really a major part of the OLE▸ design.
There are just the two where we had one before, next to Minnie Mouse. However, if you peer into the distance in the second picture, past the skeletal gasholder, there a whole load more of them.
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Electric train
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« Reply #2531 on: December 27, 2013, 19:04:43 » |
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Look - they're breeding! So, for all that I still think this look a bit of a lash-up, these things are really a major part of the OLE▸ design.
There are just the two where we had one before, next to Minnie Mouse. However, if you peer into the distance in the second picture, past the skeletal gasholder, there a whole load more of them.
I think, and I not an OLE engineer, they are mid-span anchor points and / or fixed anchor points for the wire runs for the crossovers in this area. On the Mk3 Headspan the mid-span and fixed anchor tail wires are fed through the adjacent roads to a structure (normally) in the cess, each time they fly through an adjacent road they have to have insulation cut in and the piece of wire passing through bonded to the OLE of the road its flying through ............. gets messy and prone to failure and a pain if the wire needs re-running. Why 2 portal booms upper one for the catenary wire the lower for the contact wire, between these 2 structures there will be a contact wire over lap
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Starship just experienced what we call a rapid unscheduled disassembly, or a RUD, during ascent,”
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stuving
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« Reply #2532 on: December 29, 2013, 17:42:34 » |
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I think, and I not an OLE▸ engineer, they are mid-span anchor points and / or fixed anchor points for the wire runs for the crossovers in this area. On the Mk3 Headspan the mid-span and fixed anchor tail wires are fed through the adjacent roads to a structure (normally) in the cess, each time they fly through an adjacent road they have to have insulation cut in and the piece of wire passing through bonded to the OLE of the road its flying through ............. gets messy and prone to failure and a pain if the wire needs re-running.
Why 2 portal booms upper one for the catenary wire the lower for the contact wire, between these 2 structures there will be a contact wire over lap
In addition to the (now) two on the station side of gantry 1, I counted about nine on the other side. There's a concentration of them near Kennet Bridge, which supports the idea that they are to deal with the extra wires for crossovers. There must be a specific reason for having a second rigid mounting, and I can think of a few possibles. One is for simpler mid-point or end anchoring. Another is to allow a sharp change of direction of the tensioned contact wire, to get it out of the way of live stuff, which needs a significant transverse force. The last is to mount a cable tensioner - I believe there are some that go on the gantry, and do not rely on dangly weights. But, as ever, we'll see if we wait.
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« Reply #2533 on: December 29, 2013, 17:50:52 » |
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By yesterday (Saturday) afternoon, the temporary P7 was no more. I think the scaffolding over the track at P3 was being taken down, too. At P10, the ballast had been scooped up and taken away. And there was a load of frantic (semi)final fettling on the other closed platforms.
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DidcotPunter
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« Reply #2534 on: December 29, 2013, 19:12:47 » |
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In addition to the (now) two on the station side of gantry 1, I counted about nine on the other side. There's a concentration of them near Kennet Bridge, which supports the idea that they are to deal with the extra wires for crossovers.
There must be a specific reason for having a second rigid mounting, and I can think of a few possibles. One is for simpler mid-point or end anchoring. Another is to allow a sharp change of direction of the tensioned contact wire, to get it out of the way of live stuff, which needs a significant transverse force. The last is to mount a cable tensioner - I believe there are some that go on the gantry, and do not rely on dangly weights. But, as ever, we'll see if we wait.
I'm no expert on OHLE, but I believe that the system being installed on the GWML▸ is designed by the Swiss company Furrer & Frey in conjunction with Network Rail. Furrey & Frey are also responsible for the rewiring of the Great Eastern Main Line between Liverpool St and Shenfield where the original 1949 1500V DC▸ catenary (later upgraded to 6.25kV, then 25kV AC) is being replaced. This presentation by a F&F engineer summarises the work involved. Whilst most of the original portal structures have been adapted for the rewiring some new ones have been installed. The ones pictured at the bottom of slides 18 and 25 bear more than a passing resemblance to the twin-boom portals east of Reading. I think the ones on slide 18 are located between Bethnal Green and Bow and does indeed appear to be for terminating wire runs. The one on slide 25 appears to be a mid-section portal as described earlier by Electric Train. http://www.cifi.it/UplDocumenti/torino12/35%20Rico%20Furrer%20%20%20Furrer%20Frey.pdf
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« Last Edit: December 29, 2013, 19:21:35 by DidcotPunter »
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