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Post by Deleted on Oct 23, 2007 14:56:26 GMT
At TCR eastbound, there are some odd-looking objects in among the rails or pit - looking almost like sets of coat hooks of the kind you'd find on a stand.
I only just noticed them, really, and can't describe them better, but I am sure I have never seen them before. What are they and what are they for?
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Post by railtechnician on Oct 23, 2007 16:45:15 GMT
Without a picture it's hard to say, however, could they be the remnants of the track to train CCTV transmission cable support. This cable would've run parallel to the rails just above sleeper level between the negative rail and the running rail adjacent to the positive rail, i.e. the furthest running rail from the platform. I am assuming of course that this particular track to train system has been replaced by newer technology. I know the T-T transmission cable used to fracture with vibration and was a major cause of faults with the drivers CCTV.
Brian
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Post by ongarparknride on Oct 28, 2007 9:01:10 GMT
railtechnician, I'm interested in your reply. I didn't know what it was for at the time, but noticed a lot of -apologies- really shabby bits of wood and wire in station track perimeters that appeared more consistent with a light railway than the London Underground.
I'm pretty sure now these were experiments or prototypes with feeding platform cameras into the Driver's Cab in early experiments prior to introducing current acceptable safeguards permitting One Man Operation. (OMO - with deference to the Ladies, but I suspect OMO first gained recognition in bus operators?)
I regret I cannot state a timescale for these memories, but they were mainly or exclusively on the Eastern open sections of the Central Line, that are the most likely I would have observed.
To the uninformed like myself, it was a length of 2"x 1" softwood with a wire stapled to it. I honestly can't recollect enough detail as to whether it was to the platform side of the central Neg rail, or the Off-side.
I just wondered what it was, at the time, and why it was SO INCONSISTENT with the quality I expected from the usual Permanent Way.
Might this warrant a separate "historical" thread please? With contributions from those involved with it?
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Post by railtechnician on Oct 28, 2007 14:08:04 GMT
railtechnician, I'm interested in your reply. I didn't know what it was for at the time, but noticed a lot of -apologies- really shabby bits of wood and wire in station track perimeters that appeared more consistent with a light railway than the London Underground. I'm pretty sure now these were experiments or prototypes with feeding platform cameras into the Driver's Cab in early experiments prior to introducing current acceptable safeguards permitting One Man Operation. (OMO - with deference to the Ladies, but I suspect OMO first gained recognition in bus operators?) I regret I cannot state a timescale for these memories, but they were mainly or exclusively on the Eastern open sections of the Central Line, that are the most likely I would have observed. To the uninformed like myself, it was a length of 2"x 1" softwood with a wire stapled to it. I honestly can't recollect enough detail as to whether it was to the platform side of the central Neg rail, or the Off-side. I just wondered what it was, at the time, and why it was SO INCONSISTENT with the quality I expected from the usual Permanent Way. Might this warrant a separate "historical" thread please? With contributions from those involved with it? That was definitely the track to train aka TT (not to be confused with TT meaning Tunnel Telephone!) leaky feeder arrangement. The cable which as I recall was a square section was cable tied to a board as you describe running from I think 50 metres on the approach to the platform, through the platfrorm and another 50 metres beyond. It transmitted the CCTV pictures from the platform cameras into the driving cabs. AFAIK this was not experimental at all but was the unsuccessful original transmission medium. The cable had a tendency to crack due to the direct vibration as a result of it being supported directly on the sleepers which even in the best conditions will have vertical movement. In outside locations the weather was also a factor with heat and cold changing the mechanical characteristics of the cable and making it more susceptible to damage from movement. Brian |
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Post by ongarparknride on Oct 30, 2007 4:21:19 GMT
Thank you, Brian. I don't wish to bore, but recollect what I saw was held to the wood with plastic locking ties. And the fault symptom you relate implies using a co-axial cable with a solid core central conductor which would be vulnerable to breaking on movement as you suggest. It was, overall, apparently a bodged and cheap job in total. I think I understand the basics of a "leaky feeder". I'm not aware of any commercial production of a square section cable, period. Not being pedantic, I have only ever come across circular or rectangular/oval sections. I was wrong in referring to it being "stapled" in my OP, as far as I recollect. Methinks we are chatting about rather a specialist feature, and the history of which might be sealed in the LU archives Not For Release until 2057  From my Drivers-Eye Views off Video 125, I think some improvements have been made since, as you suggest saying "unsuccessful original transmission medium" hence implying subsequent improvements. And I believe the "leaky feeder" technology might have been used in early (or even current?) tunnel communication on OMO operation communication between train operator and the Line Controller. I suspect that whilst I thank you for your input, Brian, continuing this topic might be better under a thread heading such as "Signalling and Track", as it is presumably not unique to the Central Line? That said, in the relevant period I was an irregular passenger on LU and can't recollect seeing the original wood lathe and cable arrangement on any other lines, nor on the Central Tube sections. Methinks there is quite a history of experiment, R&D, and final adopted standard here, but perhaps we are the only two blokes at DD interested in it ! Cheers, Brian, and thanks for your input on the subject. anthony |
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