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« Reply #15 on: December 05, 2008, 15:00:42 » |
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agree lowering track is an option,i believe this is going to be happening in the tunnel coming out of southampton to accomodate the continental freight wagons in the not too distant future.
Regards the forthcoming blockade of one of the twin bore Marley tunnel between Totnes and Plymouth(Engineering work between Newton Abbot and Plymouth from Monday 26 until Friday 30 January 2009) does anyone know if lowering of the track for possible future electrification is being undertaken as part of the work. No, NR» are not that far sighted enough. This work is likely to only be funded ultimately by ORR» / F/ TOC▸ for track renewals, lowering track beds often involves altering drainage which in tunnels my have to include pumps if the bed has to be lowered a significant amount. This is a lot of money to be spent on a route that if electrification were to happen it may well over a decade before it does |
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Starship just experienced what we call a rapid unscheduled disassembly, or a RUD, during ascent,”
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stebbo
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« Reply #16 on: December 05, 2008, 19:52:59 » |
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Third rail around Dawlish doesn't sound good with lots of salt water around on a windy day, but then neither does 25kv overhead.
Back to the Plymouth via Okehampton debate - but don't know where that leaves Newton Abbot/Torbay or Totnes.
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Btline
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« Reply #17 on: December 05, 2008, 21:25:35 » |
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Back to the Plymouth via Okehampton debate - but don't know where that leaves Newton Abbot/Torbay or Totnes.
Plymouth via Oak is no good, as it requires a reversal. Reopen the Heathfield line - this also retains InterCity to Torbay and NA. |
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signalandtelegraph
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« Reply #18 on: December 06, 2008, 08:00:09 » |
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[
Plymouth via Oak is no good, as it requires a reversal.
Not if you come from Waterloo  |
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Bring back BR▸
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moonrakerz
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« Reply #19 on: December 06, 2008, 09:36:29 » |
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what are the downsides to '3rd rail'
Mayor problem with 3rd rail is Elf & safety, whilst Fill in schemes are allowed, NEW 3rd rail schemes are Not premitted on Elf & Safety grounds. Right, just so that I understand this correctly; a third rail is dangerous, rails one and two carrying a train weighing hundreds of tons at 100+ MPH isn't ? Can I go away and think about that one ?  |
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6 OF 2 redundant adjunct of unimatrix 01
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« Reply #20 on: December 06, 2008, 12:40:05 » |
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what are the downsides to '3rd rail'
Mayor problem with 3rd rail is Elf & safety, whilst Fill in schemes are allowed, NEW 3rd rail schemes are Not premitted on Elf & Safety grounds. Right, just so that I understand this correctly; a third rail is dangerous, rails one and two carrying a train weighing hundreds of tons at 100+ MPH isn't ? Can I go away and think about that one ? i think safty wise for workmen on the line while services are running this can be done in a safe way with speed restrictions however dodging trains and a big piece of metal that wants to fry you is not a good combo |
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Btline
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« Reply #21 on: December 06, 2008, 15:52:19 » |
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Plymouth via Oak is no good, as it requires a reversal.
Not if you come from Waterloo If you come from Waterloo, it is slower than reversing! And there aren't enough paths into Waterloo to have sufficient fast and slow trains. Plus there would be ANOTHER reversal to get into Cornwall. No good, the GWR▸ is the best. |
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G.Uard
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« Reply #22 on: December 07, 2008, 07:36:27 » |
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Although I personally regard speculation re electrification west of Exeter as 'pie in the sky', there is a coastal section of the Hutt suburban line in Wellington NZ, which bears close comparison with the Dawlish sea wall stretch.  The NZ line is electrified at 1500v DC▸ on the overhead system and has been in use since the 1930s. Although this section is subject to storm damage, the salty atmosphere appears not to affect day to day operation and new trains are on order. |
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devon_metro
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« Reply #23 on: December 07, 2008, 11:59:20 » |
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I'm no expert on OHLE, but there must be a rust/corrosion resistant material out there that is capable of conducting sufficient electricity?
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Electric train
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« Reply #24 on: December 07, 2008, 20:50:43 » |
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I'm no expert on OHLE, but there must be a rust/corrosion resistant material out there that is capable of conducting sufficient electricity?
Plenty of them, but as all of them are metal they are liable to corrosion, Dawlish could be electrified it will require some very special engineering and it would be expensive. Third rail has been rule out by HRMI based on the 1989 Electricity at Work Act requirements for all new major route electrification, but this would not prevent infill's such Reading Basingstoke but would rule out Basingstoke Winchester Exeter. The major disadvantage of 3rd rail is the amount of line understructure. |
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Starship just experienced what we call a rapid unscheduled disassembly, or a RUD, during ascent,”
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oilengineer
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« Reply #25 on: December 08, 2008, 17:14:15 » |
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Just a comment that will baffle many but does any one know if the 25kv overhead electrification is 25Kv RMS or Peak? (RMS Root Mean Square)
To put it in layman terms the 230volt supply at home is RMS, the peak voltage is about 330volts.
The RMS is the Average voltage over 1/2 a sine wave.
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6 OF 2 redundant adjunct of unimatrix 01
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« Reply #26 on: December 08, 2008, 19:50:01 » |
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Just a comment that will baffle many but does any one know if the 25kv overhead electrification is 25Kv RMS or Peak? (RMS Root Mean Square)
To put it in layman terms the 230volt supply at home is RMS, the peak voltage is about 330volts.
The RMS is the Average voltage over 1/2 a sine wave.
quadratic mean (rms), but im often wrong... (along time since i did physics at school) |
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Electric train
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« Reply #27 on: December 08, 2008, 22:45:02 » |
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Just a comment that will baffle many but does any one know if the 25kv overhead electrification is 25Kv RMS or Peak? (RMS Root Mean Square)
To put it in layman terms the 230volt supply at home is RMS, the peak voltage is about 330volts.
The RMS is the Average voltage over 1/2 a sine wave.
It is 25kV RMS as all ac voltage values are stated. the actual system range is min 21kV max 28kV although the system can function as low as 15kV only emergency movements can happen. Typical grid intake from a 132kV grid site is 26MW and from a 400kV grid site it is 58MW, 26MW is the max that can be taken from a 132 before the single phase loading causes problems to the grid, at 400kV there less of a problem and power greater than 58MW is feasible, however the 400kV grid sites are only currently used on the WCML▸ as part of the up grade and the power distribution along the railway is different the classic system previously used on the WCML and elsewhere in the UK▸ the new system is similar to that used in France for the TGV▸ and also that used on CTRL▸ basically the distribution system on the WCML (in parts) uses a 50kV system but the trains still operate at 25kV.............. no one said electric traction systems where as easy a hornby train set |
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Starship just experienced what we call a rapid unscheduled disassembly, or a RUD, during ascent,”
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6 OF 2 redundant adjunct of unimatrix 01
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« Reply #28 on: December 08, 2008, 23:59:55 » |
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Just a comment that will baffle many but does any one know if the 25kv overhead electrification is 25Kv RMS or Peak? (RMS Root Mean Square)
To put it in layman terms the 230volt supply at home is RMS, the peak voltage is about 330volts.
The RMS is the Average voltage over 1/2 a sine wave.
It is 25kV RMS as all ac voltage values are stated. the actual system range is min 21kV max 28kV although the system can function as low as 15kV only emergency movements can happen. Typical grid intake from a 132kV grid site is 26MW and from a 400kV grid site it is 58MW, 26MW is the max that can be taken from a 132 before the single phase loading causes problems to the grid, at 400kV there less of a problem and power greater than 58MW is feasible, however the 400kV grid sites are only currently used on the WCML▸ as part of the up grade and the power distribution along the railway is different the classic system previously used on the WCML and elsewhere in the UK▸ the new system is similar to that used in France for the TGV▸ and also that used on CTRL▸ basically the distribution system on the WCML (in parts) uses a 50kV system but the trains still operate at 25kV.............. no one said electric traction systems where as easy a hornby train set wait i got it correct? |
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smokey
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« Reply #29 on: December 09, 2008, 11:16:05 » |
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So if the max voltage is 28000 volts (rms) then the overhead lines have to be able to withstand a peak of almost 40,000 volts, yes it's only at a peak for microseconds but Electrical voltage is better understand as being Electrical Pressure.
If the insulation isn't up to 40,000 it will break down.
Now to clear a Myth, is Water a conductor?
Rain Water cann't be otherwise in every rain storm overhead lines would blow up.
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