How would you electrify Dawlish?

[Hartington]

The recent stranding of a Voyager at Dawlish, having been hit by a wave, had me wondering. If (and yes, I accept it's a big if) how do you electrify along the sea wall? Water and electricity don't seem to be happy bedfellows.

 

[cf111]

The line at Saltcoats gets battered some winters:

No idea if they could do Dawlish in the same fashion, but my understanding of the issues with Voyagers was that it is to do with the onboard computers packing in when the resistor banks on the roof are hit by the salt water.

 

[Ploughman]

The same way that electric services operate in Scotland to Ayr.
http://i.dailymail.co.uk/i/pix/2014/01/03/article-2532595-1A65CFF500000578-6_964x614.jpg

You must have thought the same as me.

 

[Trainfan344]

I'd just use the same technique as Saltcoats

 

[Philip Phlopp]

The recent stranding of a Voyager at Dawlish, having been hit by a wave, had me wondering. If (and yes, I accept it's a big if) how do you electrify along the sea wall? Water and electricity don't seem to be happy bedfellows.

It's very straightforward.

I'd look to install lattice portals rather than solid masts, tighten the spacing between them to maybe 35 or 40 metres, and add metal grids at the top of the masts to protect against debris, if that's an issue.

It might be necessary to increase the tension to deal with wire deflection caused by waves/spray, so I'd suggest the Series 1 equipment rather than Series 2, if that's a consideration.

You would want to be able to isolate the sea wall electrically during extremely violent weather, and probably have provision for wire renewals in the most at risk areas of the wall, so providing tensioning and crossovers in sensible positions. I'd have thought you would want to continue to provide traction electricity to Teignmouth and Dawlish Warren during an electrical isolation of the sea wall section, so that would be provisioned accordingly.

Beyond that, maybe the use of some additional stainless steel components if there's anything that's particularly at risk from prolonged exposure to spray.

 

[HarleyDavidson]

Overhead conductor rails, as they use on the EU mainland in some of the tunnels.

 

[Railsigns]

The same way that electric services operate in Scotland to Ayr.
http://i.dailymail.co.uk/i/pix/2014/01/03/article-2532595-1A65CFF500000578-6_964x614.jpg

That's on the line to Ardrossan and Largs, not Ayr.

 

[HarleyDavidson]

Overhead conductor rails, as they use on the EU mainland in some of the tunnels.

http://www.furrerfrey.ch/en/systems/conductor_rail.html#prettyPhoto

 

[Philip Phlopp]

Overhead conductor rails, as they use on the EU mainland in some of the tunnels.

http://www.furrerfrey.ch/en/systems/conductor_rail.html#prettyPhoto

Would need too many masts to make it viable, unfortunately.

 

[gazthomas]

Are they electrifying this line? I thought not

 

[mcmad]

The problems tend not to be the construction of the OLE itself but the tripping when the waves bridge earth to OLE. Solid conductor rail won't make any difference.

 

[Domh245]

Could there not be a system similar to the system used on some French Tramways with the Ground level power supply, where the power is only switched on to a small section when the train is practically underneath it before then switching off again when the train is clear of that section.

Without paying the slightest attention to cost, if you have an insulated 25kV feeder cable buried beneath the ballast and then feeding short sections (half a tension length?) of overhead line separated by ceramic sections but without the full neutral section kit (with no phase difference as it is fed from the same source). There may need to be a longer stretch of insulator to prevent arcing damage, although said section could also double up as the activation switch for the section ahead. Thoughts?

 

[Ploughman]

That's on the line to Ardrossan and Largs, not Ayr.

Not often am I right but I was wrong again.
Got the right country though.

 

[Philip Phlopp]

Could there not be a system similar to the system used on some French Tramways with the Ground level power supply, where the power is only switched on to a small section when the train is practically underneath it before then switching off again when the train is clear of that section.

Without paying the slightest attention to cost, if you have an insulated 25kV feeder cable buried beneath the ballast and then feeding short sections (half a tension length?) of overhead line separated by ceramic sections but without the full neutral section kit (with no phase difference as it is fed from the same source). There may need to be a longer stretch of insulator to prevent arcing damage, although said section could also double up as the activation switch for the section ahead. Thoughts?

Saltcoats manages to remain operational in some terrible weather, so I'd be hesitant to start worrying about special feeding and isolation arrangements for the route until it's determined whether or not the overhead wires will trip out whilst the route otherwise remains available to traffic, or whether the overhead electrification performs correctly after the sea/weather/spray conditions are so severe the route is closed to all traffic.

There's a lot of work being done on remote isolation equipment with the installation of the SCADA remote control equipment work being undertaken, so there are options out there for isolating the route, but nothing which self isolates the route as a train passes (yet).

 

[DarloRich]

How would you electrify Dawlish?

As per Saltcoats surely.....................

 

[Carntyne]

The wires at Saltcoats usually don't come down, just a risk of a train being stuck there if there's a particularly big wave that trips everything.

Craigendoran on the North Clyde to Helensburgh also suffers the same during high tides though doesn't make for as dramatic pictures!

 

[TheKnightWho]

Am I correct in thinking Saltcoats is relatively standard, just with a stronger coating on the masts and insulation rated up to 50kV under normal conditions?

 

[QueensCurve]

Saltcoats manages to remain operational in some terrible weather, so I'd be hesitant to start worrying about special feeding and isolation arrangements for the route until it's determined whether or not the overhead wires will trip out whilst the route otherwise remains available to traffic, or whether the overhead electrification performs correctly after the sea/weather/spray conditions are so severe the route is closed to all traffic.

There's a lot of work being done on remote isolation equipment with the installation of the SCADA remote control equipment work being undertaken, so there are options out there for isolating the route, but nothing which self isolates the route as a train passes (yet).

Maybe it is not a major problem. Here is a video clip of huge waves hitting the OHLE at Saltcoates with no obvious sign of arcing:-

https://www.youtube.com/watch?v=rgSrwFlJKF4

I am pretty sure I have seen a picture of arcing at Saltcoats in a severe storm around 2009 or 2010. I think it was published by the Guardian but I can't find it online.

On a slight digression, I have seen runoff water from the roof at Crewe in heavy rain discharging directly onto the catenary with no flashover. This of course is not salt water.

 

[colchesterken]

They could upgrade a couple of preserved Westerns to pull the trains through the switched off sections
That would get me and the other spotters going west
They could do it on summer Saturdays " just for fun " would love to see a Western at full power along the sea wall again

 

[John Luxton]

I wouldn't bother electrifying but reopen Meldon to Bere Alston!

 

[L&Y Robert]

Isn't the sea-wall and cliffs at Dawlish, and the very railway itself, of special landscape value? Masts and portal structures (lattice ones, I read, with special debris screens), at closer spacings too, and contact wires and catenary (2 of each, of course) would mess up the landscape somewhat, don't you think?

 

[najaB]

Isn't the sea-wall and cliffs at Dawlish, and the very railway itself, of special landscape value? Masts and portal structures (lattice ones, I read, with special debris screens), at closer spacings too, and contact wires and catenary (2 of each, of course) would mess up the landscape somewhat, don't you think?

Think of how the rusting pile of electric trains that have gotten stranded will ruin the landscape even more!

 

[Philip Phlopp]

Isn't the sea-wall and cliffs at Dawlish, and the very railway itself, of special landscape value? Masts and portal structures (lattice ones, I read, with special debris screens), at closer spacings too, and contact wires and catenary (2 of each, of course) would mess up the landscape somewhat, don't you think?

No different to Sydney Gardens in Bath, the Royal Border bridge at Berwick upon Tweed, Edinburgh Waverley station or countless other projects. Edinburgh Waverley and Sydney Gardens are in UNESCO World Heritage sites, and the Forth Bridge, which is in line for electrification, is similarly a UNESCO World Heritage site.

The absolute most you can hope for is some architecturally sympathetic masts onto which the prevalent OLE system of the day will be mounted upon, though for most of the route, I would probably suggest twin track cantilevers mounted on the cliff side of the route would be both sensible engineering solutions and will have the least impact on the landscape.

I do seem to find myself repeatedly reminding people that a far more historically important and significant railway, the Liverpool and Manchester Railway, has successfully been electrified, with stations including Rainhill being sympathetically treated.

Those hoping to play the landscape or architecture card to stop electrification really need not bother - focus your energies on ensuring the work is done as sympathetically as possible, suggest practical and affordable options when the Network Rail and contractor teams conduct public meetings, explain to them patiently where you wouldn't want a mast or portal and suggest alternatives.

It's worth bearing in mind that the designers, consultants and engineers who draw up the plans won't know your town or village intimately so if they're missing something, kindly point it out to them instead of assuming they already know and don't care.

 

[colchesterken]

I was impressed with how they did the wiring in Paddington trainshed
it is hardly noticeable,very neat

 

[HSTEd]

Conductor rails might require more support positions (~15m max span) but it has to be remembered that the line is adjacent to a cliff face for significant distnaces and thus additional supports are probably available - indeed if nothing else masts would not stand out against a background as the cliff is only a few feet away.
(Paint them the same colour as the stone? - a sort of off-beige?)

Conductor rail also has a far simpler look to it - and is considerably more rugged.

Although it would probably be cheaper just to do a Saltcoats.

 

[34D]

Won't all the (theoretical) elecric trains through Dawlish be bi mode?

If so, surely having a short section without catenary (for both reasons) is entirely feasible?

 

[HSTEd]

Won't all the (theoretical) elecric trains through Dawlish be bi mode?

If so, surely having a short section without catenary (for both reasons) is entirely feasible?

Once you are electrifying Dawlish there is little reason not to continue to Penzance.
At which point you have electrified the entire main line in Cornwall and can dispense with the bi-modes.

 

[Philip Phlopp]

Conductor rails might require more support positions (~15m max span) but it has to be remembered that the line is adjacent to a cliff face for significant distnaces and thus additional supports are probably available - indeed if nothing else masts would not stand out against a background as the cliff is only a few feet away.
(Paint them the same colour as the stone? - a sort of off-beige?)

Conductor rail also has a far simpler look to it - and is considerably more rugged.

Although it would probably be cheaper just to do a Saltcoats.

I don't like the idea of painting masts, but I'd make an exception for a stretch at Dawlish, and it would work as excellent weather protection, provided it's done using a high quality polymer coating, of the sort favoured in the North Sea (and used on the Forth Bridge). The route will be quiet enough to allow for a few possessions to allow for re-painting every 15 years too.

DC isn't feasible for Dawlish for a mixture of safety and reliability concerns, the line suffers from weather and wave conditions that are of little concern for 25kV AC OLE, but which would short circuit 750V DC - the route had to discontinue track circuit signalling because it was difficult to deal with shorting between the tracks.

 

[HSTEd]

DC isn't feasible for Dawlish for a mixture of safety and reliability concerns, the line suffers from weather and wave conditions that are of little concern for 25kV AC OLE, but which would short circuit 750V DC - the route had to discontinue track circuit signalling because it was difficult to deal with shorting between the tracks.

I mean 25kV overhead conductor rail.
Even I would balk at third rail on that section.

 

[HowardGWR]

Once you are electrifying Dawlish there is little reason not to continue to Penzance.
At which point you have electrified the entire main line in Cornwall and can dispense with the bi-modes.

You appear to have forgotten Exeter to Bristol and Taunton to Newbury. The latter has not much higher a frequency of use than a branch line, so I would think the former would have priority and tie in with a Bristol to Brum wiring.