Great Western Main Line electrification - ongoing discussion

[whole diary]

[Western Pathfinder]

Just found this on YouTube may be of interest?.
https://m.youtube.com/watch?v=5nLwKRtfOKs&feature=youtu.be

Thanks for posting that. Interesting.  In my days on the WCML^▸ (West Coast Main Line) in the Late 1960/Early 1970s, the MK1 OLE^▸ (Overhead Line Equipment, more often "OHLE") wasn't that slack and I certainly don't remember that much uplift.  I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

My pleasure S&T^▸ (Signalling and Telegraph) thought you might find it interesting.

[paul7575]

I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

I do not think that H&S^▸ (Health and Safety) would allow that today.

I think they do.  I’m fairly sure they are still being installed, are there not a few in the Reading station area?

Paul

[Electric train]

Just found this on YouTube may be of interest?.
https://m.youtube.com/watch?v=5nLwKRtfOKs&feature=youtu.be

Thanks for posting that. Interesting.  In my days on the WCML^▸ (West Coast Main Line) in the Late 1960/Early 1970s, the MK1 OLE^▸ (Overhead Line Equipment, more often "OHLE") wasn't that slack and I certainly don't remember that much uplift.  I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

The Mk 1 may have been fixed tension in those days, very little give which surprisingly enough meant lower line speed.   The up lift of series 1 & 2 I doubt is more than Mk 3.

I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

I do not think that H&S^▸ (Health and Safety) would allow that today.

I think they do.  I’m fairly sure they are still being installed, are there not a few in the Reading station area?

Paul

Cages for signal maintenance are an option of last resort now, especially with LED signal heads, preferred methods are either from a MEWP^▸ (Mobile Elevating Working Platform) (Mobile Elevated Working Platform) aka a cherry picker or on winch / tilt over mast.

[stuving]

Just found this on YouTube may be of interest?.
https://m.youtube.com/watch?v=5nLwKRtfOKs&feature=youtu.be

Thanks for posting that. Interesting.  In my days on the WCML^▸ (West Coast Main Line) in the Late 1960/Early 1970s, the MK1 OLE^▸ (Overhead Line Equipment, more often "OHLE") wasn't that slack and I certainly don't remember that much uplift.  I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

For Series 1, the design pantograph uplift is 80 mm, with a maximum of 200 mm allowed for before bits hit each other. The allowed circumflex in a single-span overlap (which AIUI^▸ (as I understand it) is the static rise in the two contact wire heights where they are equal) is 10-70 mm. The picture doesn't look much different from those figures allowing for the foreshortening that exaggerates the bounce and floppiness of all the wires.

[SandTEngineer]

Thanks for that STUVING.  Maybe its just that the video was taken with a slightly phototelescopic lens?  By the way, did you mean 200mm and not 200m?

[stuving]

Thanks for that STUVING.  Maybe its just that the video was taken with a slightly phototelescopic lens?  By the way, did you mean 200mm and not 200m?

Yes, of course, thanks. You know the perspective is misleading because the supports and registration arms look so close to each other, on plain line where you know they aren't. It's even quite hard to see which bits are attached to which portal.

There are lots of Knightons, this must be the one between Uffington and Shrivenham - though the crossing was closed several years ago, and was named for nothing more than a copse.

[DidcotPunter]

Hmm. It was clearly taken with a telephoto lens though the uplift from the pantograph looked pretty normal to me.

Knighton is a bit more than a copse, it's a hamlet/village about a mile south of the site of the crossing.

https://www.google.com/maps/@51.5834848,-1.5930662,3a,75y,180h,90t/data=!3m6!1e1!3m4!1sh4p0dvfEfXIXEJv-p1TSYA!2e0!7i13312!8i6656

Here's the site of Knighton Crossing (before electrification), it's on the road between Knighton village and Longcot.

https://www.google.com/maps/@51.5992317,-1.6024652,3a,75y,319.26h,86.35t/data=!3m6!1e1!3m4!1sYYEmXfoIekHu-ZQ1G8oxGg!2e0!7i13312!8i6656

It was replaced by this underbridge on Claypit Lane between Uffington and Longcot which the Knighton road was diverted into.Might have been at the time HSTs^▸ (High Speed Train) were introduced in 1976 or even earlier?

https://www.google.com/maps/@51.5997639,-1.6008706,3a,75y,342.34h,101.29t/data=!3m6!1e1!3m4!1symZBAt4wGsQSgTExObcU8A!2e0!7i13312!8i6656

[stuving]

Knighton is a bit more than a copse, it's a hamlet/village about a mile south of the site of the crossing.

Fair enough - I apologise to all Knightonians about that. Mapmakers have decided that Compton Beauchamp is a more important place, for some reason.

[ellendune]

I can confirm that Knighton is a hamlet within the parish of Compton Beauchamp and although not large is a quite a high proportion of the parish as a whole.

I can also confirm that Knighton crossing was closed as part of the High Speed Train (HST^▸ (High Speed Train)) works in the 1970's. In fact Claypit lane was diverted with a new bridge constructed under the railway. The current connecting road from the road from Knighton was actually the original connection to allow Claypits lane to cross the railway at Knighton Crossing.   

Edit: VickiS - Clarifying Acronym

[Oxonhutch]

Adrian Vaughan "Signalman's Reflections" has a section on working Knighton Crossing as a school boy in the 1950s, and the role it played in regulation traffic to and from Chippenham. He also relates how the signalman of the day got its status, and hence his pay, raised by having the locals (Knightonians perhaps) use the crossing a lot more on assessment day.

[Drkpm]

PAD^» (Paddington (London) - next trains)/SWA^» (Swansea - next trains).. 1B25, Departed Swindon this morning with its “Pan still up”...Slowed to a near stop, before the Pan was dropped and the diesels started......How much are these “ Professionals “ paid ?

[grahame]

PAD^» (Paddington (London) - next trains)/SWA^» (Swansea - next trains).. 1B25, Departed Swindon this morning with its “Pan still up”...Slowed to a near stop, before the Pan was dropped and the diesels started......How much are these “ Professionals “ paid ?

Welcome to the forum, Drkpm ... I'm guessing that's a rhetorical question about salary levels?

Is that the first report of a passenger carrying train leaving Swindon westbound under electric traction - perhaps part of testing / training, and intentionally done?

[Rooke]

Travelled on 1615hrs Pad/Swansea 9 car set yesterday under the pan until BPW^» (Bristol Parkway - next trains) then diesel.

[eightf48544]

Travelled on 1615hrs Pad/Swansea 9 car set yesterday under the pan until BPW^» (Bristol Parkway - next trains) then diesel.

What about Steventon bridge just after Didcot?

Big article in Dec Modern Railways showing signage for drivers regarding dropping the pan and gong diesel to traverse the bridge. Not sure I fully understand the procedure.

[IndustryInsider]

Big article in Dec Modern Railways showing signage for drivers regarding dropping the pan and gong diesel to traverse the bridge. Not sure I fully understand the procedure.

Basically the driver selects diesel mode at Moreton cutting, runs on diesel through Didcot and as far as Causeway and at a section of Over-Head Line Equipment (OHLE) that has been specially tensioned, indicated by lineside signage, at Causeway they select electric mode to raise the pan and continue on electric to Swindon where diesel mode is once again currently selected.

Signage consists of an advance warning, a raise pan sign and a 'too late, don't raise pan sign!' at the end of the section.  If you leave it too late you can't change over to electric unless doing less than 20mph.

There are no in cab indications, though eventually the APCo (Automatic Power Changeover) system should be commissioned which does the changeover automatically.

Edit: VickiS - Clarifying Acronym