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Post by malcolmffc on Jan 12, 2019 17:34:38 GMT
Throughout the LU network, including the open sections, there are cables running alongside the tracks, all in different colours. What are these cables, and why aren’t they needed on National Rail routes (including electrifed railways?)
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rincew1nd
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Post by rincew1nd on Jan 12, 2019 17:39:53 GMT
Network Rail has cables too, but tends to put them in troughs rather than the racking that LU uses.
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Deleted
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Post by Deleted on Jan 12, 2019 18:17:11 GMT
You have signalling cables, air main, telephone cables, connect fibre, HV cables the list is endless really
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Post by bearbin on Jan 12, 2019 21:15:13 GMT
I feel like LU tends to have more thick cables than NR sections - maybe for DC power in parallel, unless it's just my imagination? The small troughs certainly wouldn't really work to take more than a few thick cables.
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Tom
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Signalfel?
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Post by Tom on Jan 13, 2019 9:10:25 GMT
Yes, I think there are more thick High Voltage cables. LU has an internal HV distribution network, rather than NR who seem to take power from the grid locally.
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Tom
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Signalfel?
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Post by Tom on Jan 13, 2019 9:11:20 GMT
You have signalling cables, air main, telephone cables, connect fibre, HV cables the list is endless really You forgot the two most common ones - 'unknown' and 'redundant'!  |
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Post by Dstock7080 on Jan 13, 2019 9:58:20 GMT
LU are starting to use lineside troughs for 4LM in some areas, seem to be composite/plastic material.
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Post by tjw on Jan 13, 2019 18:30:03 GMT
LU are starting to use lineside troughs for 4LM in some areas, seem to be composite/plastic material. I saw those troughs the other day at Ricky, did not seem to go anywhere as yet. They seem to be the size of the old SR power troughing and not the size of the smaller signalling trough that seems to be extinct part from a few preserved railways. Good idea making it out of plastic, the concrete was rather heavy, and did not protect the cables when the P-Way chose the nice flat lid as an ideal place to build a fire to burn off various bits of the lineside. "You forgot the two most common ones - 'unknown' and 'redundant'!" That had always been my suspicion it is nice to know my guess was correct. |
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Post by orienteer on Jan 19, 2019 22:26:59 GMT
The original 4LM plan was to start with the simpler, outer areas and work inwards. Hence the Uxbridge branch had new racks installed about ten years ago, which have remained unused ever since. Trust they'll still be used when 4LM reaches Uxbridge, it is now planned to be the last stage.
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Post by phil on Jan 20, 2019 3:44:34 GMT
Throughout the LU network, including the open sections, there are cables running alongside the tracks, all in different colours. What are these cables, and why aren’t they needed on National Rail routes (including electrifed railways?) on Network Rail (and British Rail before them) lineside cabling is usually placed in concrete troughing at ground level - which can be hard to see as they can get camouflaged by excess ballast / vegetation or dirt from cutting sides. In in some parts of the North East, cable theft was such a problem NR have had to restore to burying them 10ft underground! One big advantage of putting such cabling low down is it facilitates the use of flails and other mechanised vegetation clearance plus it’s supposedly maintance free. On the other had having it enclosed in close proximity to the ground makes damage by rodents / rabbits (the treat the troughing as handy transport routes away from predators). |
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Post by phil on Jan 20, 2019 4:01:11 GMT
Yes, I think there are more thick High Voltage cables. LU has an internal HV distribution network, rather than NR who seem to take power from the grid locally. All NR electrical power is taken in from the National Grid at strategic locations then distributed along the line. However it’s not simply a case of taking a feed off any old pole / pylon route - Traction power has to come from the 33KV super grid.... ....which is why Overhead electrification on the GWR will go as far as Chippenham - it’s the only place NR can tap into a suitable HV supply between Swindon and Bristol. Similarly the overhead supply at Kettering will actually be fed from a location near Market Harborough as there is no suitible 33KV route at Kettering. Obviously with DC electrification being as inefficient as it is, more frequent substations are needed - which means that some HV distribution is still handled by NR as the local grid supply is not powerful enough to act as a supply point to the substation* * This is a particular problem in places line Dorset and East Sussex - which is part of the reason the late 1980s electrification schemes have significant limitations on the length / number of trains that can be supported. In fact this is one of |
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