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paul7575
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« Reply #510 on: December 31, 2011, 18:35:50 » |
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It is also seems current best practice is to avoid S&C▸ components on any sort of gradient - so that also extends the whole layout.
Some of the new crossovers are very much on a gradient! Another bit of 'duff gen' from someone at one of those NR» public displays then...  Paul |
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« Last Edit: January 02, 2012, 19:36:03 by paul7755 »
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paul7575
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« Reply #511 on: January 01, 2012, 17:18:20 » |
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Not clear where the delay occured though. Here's a possible theory, purely from the video though. Looking at the procedure shown, the foundation pads (or footings) seem to have been built integrally with the bridge sides, prior to it moving. See at 1m 18s. I think this means they would have to excavate wide trenches to very exact dimensions with very accurate depths and more importantly accurate flatness and compaction. It may just be that heavy rainfall slowed down the digging and levelling. Normally footing concrete would be poured into the ground, then it would self-level to an extent, and be allowed a decent time to set hard, the method seen here seems to be designed specifically for speed - but can be slowed by rain. Paul |
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IndustryInsider
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« Reply #512 on: January 01, 2012, 21:26:19 » |
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Another bit of 'duff gen' at one of those NR» public displays then... I'm sure it's just a question of space constraints. Ideally, on the level is best, but when you haven't got the room. Bear in mind the distance between Spur Junction and the buffer stops is less than a mile and in that space you have to fit all the extra crossovers for the three platforms and the crossovers to the route that will eventually be reinstated under the GWML▸ to the north side of the station. I'd have thought that as long as any gradient remains constant, then it shouldn't make too much difference. |
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To view my GWML▸ Electrification cab video 'before and after' video comparison, as well as other videos of the new layout at Reading and 'before and after' comparisons of the Cotswold Line Redoubling scheme, see: http://www.dailymotion.com/user/IndustryInsider/ |
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paul7575
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« Reply #513 on: January 02, 2012, 15:54:49 » |
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Another bit of 'duff gen' at one of those NR» public displays then... I'm sure it's just a question of space constraints. Ideally, on the level is best, but when you haven't got the room. Bear in mind the distance between Spur Junction and the buffer stops is less than a mile and in that space you have to fit all the extra crossovers for the three platforms and the crossovers to the route that will eventually be reinstated under the GWML▸ to the north side of the station. I'd have thought that as long as any gradient remains constant, then it shouldn't make too much difference. In hindsight, I wonder if they were trying (without much success) to explain that the additional S&C▸ couldn't be fitted on a constant slope of the same length of the original gradient, so as well as the move to allow for longer platforms the sloping section had to be lengthened overall so that it could be fitted? Does that makes sense...  Paul |
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ellendune
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« Reply #515 on: January 02, 2012, 22:22:20 » |
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It also has a link to a better time lapse video of Cow Lane and some You Tube Video of Platform 4.
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« Last Edit: January 02, 2012, 22:39:39 by ellendune »
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bobm
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« Reply #516 on: January 04, 2012, 18:30:42 » |
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Old habits die hard. I was on Reading Station last week and because of signalling problems east of Reading they were doing a lot of manual annoucements. The person doing them kept getting his platform 7s confused with his platform 4s causing much amusement among the despatch staff on the new platform 7. It obviously got back to him as he was trying to avoid a fit of the giggles.
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BerkshireBugsy
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« Reply #517 on: January 04, 2012, 18:42:48 » |
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That was happening tonight - staff getting p4 and p7 mixed up resulting in much confusion !
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onthecushions
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« Reply #518 on: January 05, 2012, 20:25:09 » |
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I wonder whether it would be better to rename platforms as A, B, C, etc., when numbers must change. That way staff and customers would have to think in terms of the new titles. When everything had settled down, the platforms could revert to their final numbers.
Glad to see that the Windsor Lines have kept number 4 - beautiful job the new work is.
OTC
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mjones
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« Reply #519 on: January 05, 2012, 21:22:36 » |
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.... Note the position of the buffer stops, now a good coach length away from the physical end of the platform. Modern safety standards I expect, though how many thousands of people will just miss their train over the coming years with that extra distance to go I wouldn't like to guess!
I was very surprised at how far down the new platform the buffer stop now is. Is this really justifiable, in cost-benefit terms, given TPWS▸ , the crash-worthiness of modern rolling stock etc? I'd be interested to know the impact on the cost of the scheme- that's a fair length of additional platform constructed and, given the constraints on space at the other end, must have had an effect on the work necessary to accommodate the new junction. |
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paul7575
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« Reply #520 on: January 06, 2012, 11:17:31 » |
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It is because the new devices are not actually traditional fixed 'buffer stops', but 'friction arresters'. If you look closely you'll see that there are fitted clamps allowing the structure to slide along the rail head, and as it moves backwards it gradually impacts on more rail clamps, and these increase the friction progressively, thereby slowing the train gradually. Friction arresters are the new standard, they are being fitted all over LU as well. Unless you can fit the sort of hydraulic buffers (the big pistons) seen at Waterloo, the arrester is a modern way of giving a gradual stop rather than a slow speed collision.
You have to consider also that TPWS▸ etc will not stop a train sliding under worst case railhead conditions, whether caused by ice or leaf fall.
Paul
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mjones
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« Reply #521 on: January 06, 2012, 14:28:16 » |
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Paul,
I realise how they work, and that this is now the current standard, but what I'd like to know is whether the additional cost involved, if the new platform had to be made longer than would otherwise have been the case, is justified by the reduction in risk achieved. Clearly the risks of the older style buffers weren't considered unacceptable, otherwise thousands of trains wouldn't still be allowed to stop at them every day across the country.
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ellendune
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« Reply #522 on: January 06, 2012, 19:33:56 » |
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Will they be fitted to platforms 5 & 6 when the work is completed on them?
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mjones
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« Reply #523 on: January 06, 2012, 19:50:43 » |
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I assume they would have to be as both platforms are being significantly rebuilt so would have to comply with the latest standards. One has already been placed at the end of P5, although it doesn't look as if it is fitted in its final position yet.
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