Eurostar Infrastructure?

[Whistler40145]

Substations on 25kV AC supplies can be positioned at greater distances.

 

[Hydro]

Yes....?

 

[es373]

Tim, that's a given one mate

DC isn't as complicated hydro, but its a lot bulkier, heavier as such. Its a pain in the arse if I'm honest.

 

[Barrett M95]

It's cheaper than AC, and simpler. Reliability is much of a much, only the winter tends to have an effect on DC lines, and even that's less of a problem if the de-icing programme is managed well. Once it's installed it's quite hard to break CRE, unlike OLE which comes down in fairly catastrophic terms comparatively easily.

DC falls down on the frequent substations and supply infrastructure needed to keep the voltage up over any substantial distance. I gather the equipment isn't particularly complex, but it's the amount of it that's the headache.

That said, LGV overheads can and do survive gale force winds, snow and ice without any problems. It's more of an issue on classic lines where trees, branches or the closer proximity of other things that damages or brings the wires down - not the weather conditions themselves. (LGV have larger lineside clearances).

I was once on a train sat at Prestwick Airport station - which if anyone knows it, it is VERY exposed to the coastal storms that often batter that part of the world in late autumn. The wind and rain were hammering the side of the train - very violent. I looked up and the catenary was swaying and vibrating like a loose guitar string, but the train moved off just fine - plenty of wheel slip, but one can't blame that on the OLE. I remember being impressed that the catenary was able to function so well while being subjected to all that a west of Scotland winter could throw at it.

 

[Hydro]

I was thinking more of pan damage, and pan/wire dewirements. OLE damage tends to turn into a job stopper easier.

DC is fine for what it was intended, a large EMU outer suburban network not over 100mph. Running the likes of large electric locomotives and TGV style trains on it was never what was envisaged. Eurostar on 750dc was almost a stopgap measure, HS1 was being discussed practically at the start of Eurostar services. 92's are subject to operating restrictions in terms of how many per section can power, and even 2 x 73's are restricted in a few places (1 x 73 is restricted to series only on Lymington!).

 

[ChrisCooper]

I think the ECML problem with wind is that the spacing between masts is too long on some sections, especially those exposed to the winds where it really is the East *Coast* Main Line. The wind can blow the contact wire so at mid span it goes off the edge of the pantograph.

 

[Barrett M95]

Short video showing OLE as it should be:

http://www.flickr.com/photos/railwayphotographic/6058940723/

 

[es373]

A bit faster then that would be on the money

 

[Yew]

WRT ECML OHLE (thats a lot of acronyms)

I think we had a post from old timer a few months ago about the ECML OHLE, I cant remember what it was exactly but the gist I got from it was.

- The OHLE was originally installed for 100mph operation
- It was then modified for 125mph operation, but the span lengths where kept the same.
- Because of the increased 'waveyness' the pressure from the pantographs on the wire had to be increased, and somehow that causes more failures.


Hopefully someone will be able to come along and provide a more accurate explaination. and one that isnt based on me half remembering something and hence could be completely wrong

 

[es373]

Adding more pressure to the pantograph pneumatic circuit will cause more failures as you get a so called wave effect.
Its pretty much a bowed bit of wire that travels in front of the pantograph which pretty much can and does tear down catenary and such as if you haven't noticed, the contact wire isn't very tight. It's pretty loose of anything.

I don't know about other EMU TMD's but our panto's are checked on a very regular basis