Deleted
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Post by Deleted on Mar 27, 2014 9:16:15 GMT
The underground system, above ground of course, always seems blighted with wires and cables above ground, is there any reason for this?
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Post by phillw48 on Mar 27, 2014 15:40:43 GMT
You don't have room in a tunnel to dig a trench for cables. Most of the early electrified Sub-Surface lines were in tunnel as were the tube lines. Also it made replacement easier.
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Deleted
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Post by Deleted on Mar 27, 2014 17:37:35 GMT
Thanks for that, they seem so unsightly above ground
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Tom
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Post by Tom on Mar 28, 2014 8:20:49 GMT
A well maintained neat cable run is a joy to behold. Unfortunately the majority are not like this.
Trench based runs tend to attract more vermin eating cables, on the underground this would be a unacceptably high risk of causing delay. Some ducting and troughing is used but it isn't the preferred method.
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rincew1nd
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Post by rincew1nd on Mar 28, 2014 8:28:33 GMT
Else where I have laid a duct to put cable in, the pipe was marked WATER, it was explained that it is big enough to get the required cable in, but too small for the little nibblers to get in.
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Chris M
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Post by Chris M on Mar 28, 2014 10:31:26 GMT
Trench based runs tend to attract more vermin eating cables Vermin-eating cables sound like a great idea!
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Post by Hassaan on Mar 28, 2014 17:19:19 GMT
I think having all cables attached to brackets next to walls/fencing is far better than what you see on third-rail NR with a pile of 750v cables just randomly thrown on the ground next to the conductor rail. And South West Trains have had several problems with power cables catching fire in the last 2 months.
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Post by melikepie on Mar 28, 2014 17:22:59 GMT
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Post by railtechnician on Mar 28, 2014 19:39:02 GMT
A well maintained neat cable run is a joy to behold. Unfortunately the majority are not like this. Trench based runs tend to attract more vermin eating cables, on the underground this would be a unacceptably high risk of causing delay. Some ducting and troughing is used but it isn't the preferred method. I agree that a neat cable run is a joy to behold just as lacing, stitching and forming of cables into neat 'boxes' and tapered skinners is also a mark of a quality installation. Unfortunately cable dressing into trackside and tunnel runs was allowed to deviate from standard in the 1980s at a time when there was a massive expansion of communications across the combine but little expansion of the cable runs even though it must have been obvious to the drawing office that the single comms shelf provided in the majority of bracket runs was inadequate to take the 104 and 74 pair main cables installed for the telephone network uplift let alone all the other comms services that followed. Of course within relay rooms and IMRs the old methods of installing and dressing wiring were not cost effective and wiremen were not allowed the amount of time that would once have been taken to wire up racks and bays. These days LUL uses ladder runs, admiralty tray and cable ties for quickness but they allow sloppy practice although a decent skilled wireman will always be able to do a decent job with any method of installation. The days of dressing individual cables into set positions within a bracket run or form as was the discipline when I began my LT service is long gone as a result of cost and IMO a relaxation of installation standard. I recall being told by my chargehand in my first year on the job that in former years new wiremen were not allowed in equipment rooms until they had spent at least three months wiring up trackside locations under close supervision and that bad workmanship would not be tolerated, thus some wiremen were permanently banished to work at trackside and forbidden to enter such rooms. All my cable and wiring skills were learnt before I began my LT career, cable dressing, forming, lacing and box stitching being my favourite tasks in my previous career as a Telephone Engineer.
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Post by John Tuthill on Mar 28, 2014 19:43:27 GMT
A well maintained neat cable run is a joy to behold. Unfortunately the majority are not like this. Trench based runs tend to attract more vermin eating cables, on the underground this would be a unacceptably high risk of causing delay. Some ducting and troughing is used but it isn't the preferred method. I agree that a neat cable run is a joy to behold just as lacing, stitching and forming of cables into neat 'boxes' and tapered skinners is also a mark of a quality installation. Unfortunately cable dressing into trackside and tunnel runs was allowed to deviate from standard in the 1980s at a time when there was a massive expansion of communications across the combine but little expansion of the cable runs even though it must have been obvious to the drawing office that the single comms shelf provided in the majority of bracket runs was inadequate to take the 104 and 74 pair main cables installed for the telephone network uplift let alone all the other comms services that followed. Of course within relay rooms and IMRs the old methods of installing and dressing wiring were not cost effective and wiremen were not allowed the amount of time that would once have been taken to wire up racks and bays. These days LUL uses ladder runs, admiralty tray and cable ties for quickness but they allow sloppy practice although a decent skilled wireman will always be able to do a decent job with any method of installation. The days of dressing individual cables into set positions within a bracket run or form as was the discipline when I began my LT service is long gone as a result of cost and IMO a relaxation of installation standard. I recall being told by my chargehand in my first year on the job that in former years new wiremen were not allowed in equipment rooms until they had spent at least three months wiring up trackside locations under close supervision and that bad workmanship would not be tolerated, thus some wiremen were permanently banished to work at trackside and forbidden to enter such rooms. All my cable and wiring skills were learnt before I began my LT career, cable dressing, forming, lacing and box stitching being my favourite tasks in my previous career as a Telephone Engineer. I too learnt my cable lacing skills as a GPO engineer. One 'tool' you made for yourself was a small screwdriver with a notch cut in it to help you lace onto existing cables. Cable ties may be quicker, but it's still nice to see a quantity of cables which have been laced. (The PABX room in the Bank of England was one of the best I was involved in)
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