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Author Topic: Great Western Main Line electrification - ongoing discussion  (Read 109744 times)
Electric train
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« Reply #390 on: October 17, 2018, 10:47:01 am »

A defective pantograph seems the likely cause with defective overhead a distinct possibility. Either can result in the overhead getting caught UNDER the pantograph and pulling down the wires.
I'm struggling to see, in my mind, how that happens. All I can think of is the pantograph lifting, hitting the overhead line and not stopping but continuing, pushing the line to one side and getting it trapped underneath. Seems kind of complicated though.  Huh

It happens for a number of reasons which leads to the Pan horns (the red bits in my Avata) hooking over the wire which rips the wire down and even removing Pan from the train roof (its designed to do that)


Reasons -

  • OLE contact wire miss aligned, insufficient tension or incorrect stagger

    Track miss aligned, incorrect Cant, track dip, incorrect slew etc

    or a combination of the 2

    The Pan head is defective / miss aligned

    The tarin suspenstion is out of tolerance

    or a combination of the 2


    And or a combination of all of the above

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IndustryInsider
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« Reply #391 on: October 17, 2018, 10:53:51 am »

Iím hearing reports (unconfirmed) that the pantograph was raised at 105mph in an area where it is not tentioned enough for that to happen.  There are specific rules locations where you can raise on the move at speed.

So, driver error is a possibility.
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To view my GWML Electrification cab video 'before and after' video comparison, as well as other videos of the new layout at Reading and 'before and after' comparisons of the Cotswold Line Redoubling scheme, see: http://www.dailymotion.com/user/IndustryInsider/
a-driver
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« Reply #392 on: October 17, 2018, 11:41:11 am »

Iím hearing reports (unconfirmed) that the pantograph was raised at 105mph in an area where it is not tentioned enough for that to happen.  There are specific rules locations where you can raise on the move at speed.

So, driver error is a possibility.

It is possible.  Raising the pan at over 20mph in a non-designated area is a big no no.
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Bmblbzzz
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« Reply #393 on: October 17, 2018, 12:06:21 pm »

A defective pantograph seems the likely cause with defective overhead a distinct possibility. Either can result in the overhead getting caught UNDER the pantograph and pulling down the wires.
I'm struggling to see, in my mind, how that happens. All I can think of is the pantograph lifting, hitting the overhead line and not stopping but continuing, pushing the line to one side and getting it trapped underneath. Seems kind of complicated though.  Huh

It happens for a number of reasons which leads to the Pan horns (the red bits in my Avata) hooking over the wire which rips the wire down and even removing Pan from the train roof (its designed to do that)


Reasons -

  • OLE contact wire miss aligned, insufficient tension or incorrect stagger

    Track miss aligned, incorrect Cant, track dip, incorrect slew etc

    or a combination of the 2

    The Pan head is defective / miss aligned

    The tarin suspenstion is out of tolerance

    or a combination of the 2


    And or a combination of all of the above

I hadn't realized the pantograph had 'horns'. Cheers!
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Adelante_CCT
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« Reply #394 on: October 17, 2018, 12:58:28 pm »

Has there been any movement on when they expect the lines to reach Cardiff? Itís all gone quiet after they announced the delay....

This Q came up at the GWR Stakeholders Conference yesterday & Andrew Haines, MD, said next summer, if I remember correctly.

The latest delivery enhancement plan has the wires ready to be switched on in July, available to be used by passengers by November, although likely the first planned passenger service would be January (2020)
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IndustryInsider
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« Reply #395 on: October 17, 2018, 02:03:57 pm »

Which is why GWR were secretly pleased that timetable changes nationwide were deferred as it gave them another cause to blame.
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stuving
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« Reply #396 on: October 17, 2018, 03:05:52 pm »

... delivery enhancement plan ...

I take it you meant the Enhancements Delivery Plan - but their delivery couldn't half do with some enhancement too!
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TonyK
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« Reply #397 on: October 17, 2018, 03:36:15 pm »


I hadn't realized the pantograph had 'horns'. Cheers!

A pantograph is a much more sophisticated piece of kit than most people, me included, realise.
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Clan Line
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« Reply #398 on: October 18, 2018, 07:58:50 pm »

I was in Bath and Swindon this morning..............I think I now understand why the good citizens of Bath were not exactly enthusiastic about having OHLE through their city !






What a mess !
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bignosemac
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« Reply #399 on: October 18, 2018, 08:08:27 pm »

Who said the camera never lies?

Telephoto's narrow depth of field making that second image look far more cluttered than reality.

To say nothing of four tracks approaching a major interchange versus the two tracks through Bath.

A supposition, but if Brunel had had the option of overhead electrification I'd wager he'd have used it. Residents and users of the railway through Bath should understand that this is a working railway and not some heritage tourist attraction to be preserved in aspic.

The wires will come to Bath. It won't be permanently canned on heritage grounds. Deferred a few more times on cost grounds maybe, but the knitting will arrive sometime in the 21st century.
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martyjon
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« Reply #400 on: October 18, 2018, 08:15:44 pm »

I was in Bath and Swindon this morning..............I think I now understand why the good citizens of Bath were not exactly enthusiastic about having OHLE through their city !

What a mess !

But Bath is not a station throat with 6 reversible lines leading to 14 platforms.
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Bmblbzzz
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« Reply #401 on: October 18, 2018, 08:25:44 pm »

OHLE is not pretty. It does not match in style Georgian buildings or Roman remains. It is less ugly than the Colonnades and Waitrose development, the adjacent Hilton, the Southgate development. Had it arrived twenty years ago, it would have been a perfect match for the gasometers that stood on Midland Road and old Stothert & Pitt site. Had it arrived fifty years ago, it would have been viewed as a wonder of engineering to compare with the canal and bridges in Sydney Gardens.
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johnneyw
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« Reply #402 on: October 18, 2018, 08:53:01 pm »

To me OHLE within the confines and context of a modern railway is quite visually pleasing. I am pretty sure I'm not part of a majority view there but I do think that electrification though Bath will not be as obtrusive as some fear.
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« Reply #403 on: October 18, 2018, 08:58:33 pm »

It's obtrusive when you look along the track, but usually not when you look across.
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Oberon
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« Reply #404 on: October 18, 2018, 09:52:57 pm »

Every time I see the GWR catenary I am surprised how much more heavy duty is seems from other electrified main lines. Is part of the project's problem that it is over-engineered?
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