Ben
fotopic... whats that?
Posts: 4,282 
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Post by Ben on Nov 9, 2010 16:10:48 GMT
Looking at the picture of Stanmore in the 8th Nov quiz, the amount of seperate bits of wooden ramping looks very untidy and presents an increased number of trip hazards for trackwalkers, not to mention an increased workout presumably for current shoes.
Why aren't multiple small adjacent ramps made as one large bit? For example in the diamond there are four ramps fairly close to each other. Would it not reduce wear and tear if they were combined into a wooden 'x'? Or even just plank the entire diamond over in the middle?
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Deleted
Deleted Member
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Post by Deleted on Nov 9, 2010 18:13:33 GMT
It would make access to track components, chairs and clips etc, difficult, not to mention it might make a defect with a sleeper invisible. Inspection would mean removing the 'decking' [of wood!] each time inspection was required. And such would have to be put back each time; there's then the risk of it being put back incorrectly....
Also, it would have to be made to fit to exact measurements, probably on site. No two crossovers are of the same dimensions, even if outwardly they look similar.
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Ben
fotopic... whats that?
Posts: 4,282
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Post by Ben on Nov 9, 2010 21:26:27 GMT
Most Diamonds are prefabricated though aren't they, so the info could just be gained from the civils drawings of them?
Was thinking about the access problem, could fit like a table top fitting in a socket of the right size, kinda?
Could there be a cost justification though?
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Post by railtechnician on Nov 12, 2010 0:49:31 GMT
There are standard ramps for trainstops, chairlock units and standard 4' point layouts but even so due to no two layouts of anything being identical anywhere on the system most are trimmed to fit the exact location. The coffins for 6' point layouts can be shop made and trimmed on site or sometimes are constructed on site from raw material. I don't think I ever replaced any existing woodwork without having to trim it to suit. Generally only wooden ramps are seen but there are still some experimental reinforced fibre glass ones around such as those on the crossover outside Acton East IMR which have been there for many years.
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Tom
Administrator
Signalfel?
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Post by Tom on Nov 12, 2010 23:41:14 GMT
The ramps referred to are known as 'slipper runs' and are positioned in the shoe path for the negative shoe - I guess to assist a low one across rather than have it broken off.
As for standard dimensions of point metalwork; whilst various non-standard arrangements apply moves are being made to building up Points and Crossings from standard items.
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Post by railtechnician on Nov 13, 2010 3:06:17 GMT
The ramps referred to are known as 'slipper runs' and are positioned in the shoe path for the negative shoe - I guess to assist a low one across rather than have it broken off. As for standard dimensions of point metalwork; whilst various non-standard arrangements apply moves are being made to building up Points and Crossings from standard items. 'Slipper Runs' is a term I never heard in all my years of service, however, I am not surprised, is it a P-Way description? As for pointwork I had thought that all existing layouts were built from standard crossings (either cast or constructed), stocks and switches with set numbers of slide chairs and chog chairs according to 'standard' turnout lengths etc. I do appreciate that there are some 'odd' arrangements of such components such as 20W (IIRC) at Kings Cross Piccadilly which ISTR have different length switches (A & B I believe) to accommodate the tight radius into the KX Loop. I expect there must be other places with similar arrangements. Obviously on new lines there has been a trend to install higher speed turnouts and I guess that that and new point mechanisms/machines will eventually lead to more standardisation over time. Mind you I don't suppose standardisation across the combine will happen any time soon considering the cost of the equipment for a point layout these days, last I heard it was a hefty 5 figure sum per turnout although I suspect that was for a new layout rather than a replacement. |
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