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Was there not an incident at Rugby years ago where a loco failed to switch off for a neutral section? 

 

I was told it rained molten copper, and a large chunk of a transformer from the local substation was found in some ones garden half a mile away.

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There is a difference between dropping the pan to allow coasting and switching the power off at neutral sections. Unless power to the train is switched off when going through a neutral section, there is a very real risk of drawing an arc across the neutral section

During the Eurostar "classic" lines period, we used to end up regularly replacing the neutral section insulators on the Down at Saltwood Jn for precisely this reason. The arc from each train being drawn across the beads (despite arcing horns) would gradually damage them.

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Yes. If you're in the coach with the pan you can hear the bang of the circuit breaker as well. At least on a 350 you can, not certain about pendos.

Yes, you can hear them operate in the pendo coach that happens to have the pan up.

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Back to the GWML with the march of the masts.  Looking east at Twyford today the masts are gradually marching westwards in Twyford cutting on the Down side (they are nowhere near so prolific as yet on the Up side.  Although not visible in this phot as far as can be seen they look to now be in place on the Downside all the way from Ruscombe to the mast immediately in rear of the signal in this view.  There are also a couple - at least - of booms in place as can be seen.  They can't yet go any further as little more than trial digs have been carried out for some bases at Tewyford while others have simply had their position marked (although that was done so long back many of the paint marks have since worn off).  However most mast bases now appear to be in place west of Twyford station with two big reinforced concrete ones (outer tube plus reinforced concrete centre with the bolts set in the concrete) now complete in the car park.

 

Mast bases are also gradually advancing westwards in Sonning Cutting with probably only a handful left to do on the Down side where it looks as tho' most trial digs are complete, Up side not so clear but some bases are definitely in place in the cutting.  There is also a small fleet of road-rail machines based at Lands End - presumably for further base pile driving and other jobs.

 

Some action might be expected soon at Twyford as one cover has been marked 'mini dig/pile' on the centre platform while another has been back filled and the area  tarmaced while a third, near the back filled one, looks also to have been marked up for work.

 

Click on the pic to enlarge

 

post-6859-0-68739100-1469628834_thumb.jpg

Edited by The Stationmaster
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Assuming the Driver can see the two boards - one to open the circuit breakers and the other to close them - then there is  o problem and it seems to work perfectly well in France (and presumably on HS1 nee CTRL).  If it has worked in France, and elsewhere on the mainland, for many years seemingly without any problems then I don't really see why it shouldn't work in Britain.  But then equally until the arrival of the Class 800 there seems to have been some sort of major hang-up in Britain (possibly down to less than robust ohle in some places?) about raising and lowering pantographs at speed for whatever reason  - including traction current arrangement changeovers.  Eurostar generally did pretty well at lowering shoes onto the conductor rail at 100mph (although they weren't always as inclined to rise as they should have been) and raising and lowerng pantographs when coming off/going onto 3rd rail (albeit with two 'incidents' over the years where pans were raised at the wrong time.

 

SNCF has no compunction whatsoever about raising and lowering pans at LGV maximum speeds and it look as Class 800 will be doing the same in Britain (although not quite at LGV speeds of course)

 

On the LGVs and HS1 the TVM system also warns the driver about neutral sections and power changeover points.

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Been reading about the work in the Severn Tunnel   ,why are they not concreting the surface or would this cause more problems    regarding the water ingress?

 

What water ingress?  From what I have seen the lower part of the Severn Tunnel is dry - far drier than some other tunnels I have come across (including the Channel Tunnel where there are occasional puddles in the four foot.  the Welsh end is a bit wet but most of that comes, I think, from outside the tunnel.

 

The big problem in the past with electrickery (for signalling purposes) in the Severn tunnel has been the atmosphere which - not surprisingly in view of the rate of water flow through the drainage channels - is inclined to high humidity hence track circuits were never reliable.

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Just been thinking (!).

 

Will this be the first bit of electrified railway in Wales? Does Northern Ireland have anything electrified either?

 

Just wondering.....

If you discount the Swansea and Mumbles which was a rel railway then I think that there as a standard gauge branch to an ordnance factory somewhere on the Gower peninsula or thereabouts that was electrified on overhead.  However it will as far as I know be the first main line electrification.

 

Jamie

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Well, all that water that causes

and needs those big pumps.

Regards

 

Concreting over the Great Spring or concreting the drains which lead into the Tunnel would not be entirely realistic ideas I expect.  the rate of flow from the Great Spring is in tens of millions of gallons per day - if not pumped out the lowest part of the tunnel would flood to crown in well under 24 hours even though the channel leading down to the pumping point is lower than the main tunnel and I don't quite see how the tunnel could b stopped from being a sump for run-off water flowing into it without pumping out that water where it actually runs into the tunnel.  The last time I was down there - albeit a good many years ago the AME assured us that inflow through the lining from the river is as near non-existent as makes no difference. 

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If you discount the Swansea and Mumbles which was a rel railway then I think that there as a standard gauge branch to an ordnance factory somewhere on the Gower peninsula or thereabouts that was electrified on overhead.  However it will as far as I know be the first main line electrification.

 

Jamie

I hadn't heard about any electrified track on the Llanmorlais branch- certainly the Gowerton end showed no signs of any such thing. In the late 1950s/early 1960s, the Llanelly and Mynydd Mawr line had been proposed for electrification, to cope with the high volumes of traffic (which never materialised) from Cynheidre. Some resignalling work was carried out, but nothing else. There was a power station (Roath?) which had an internal line that was electrified; Brian Rolley has written about it.

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There was an electrified railway in the Llechwedd quarry.

 

The Portmadoc, Beddgelert and South Snowdon Railway was proposed as an electric railway, but apart from the power station, the railway was not built (though parts of the proposed trackbed later became the WHR).

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There was an electrified railway in the Llechwedd quarry.

 

The Portmadoc, Beddgelert and South Snowdon Railway was proposed as an electric railway, but apart from the power station, the railway was not built (though parts of the proposed trackbed later became the WHR).

I believe that the proposed electrification was the reason for the generous loading gauge through the Aberglaslyn tunnels.

 

Jamie

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