Great Western Main Line electrification - ongoing discussion

[whole diary]

[Electric train]

NR^» (Network Rail - home page) will always consult with the local Authority planners on any structure, unless it is covered a TWA and even then NR will notify the local Authority when it intends to carry out the works.

Things like road closures and section 66 have to be applied for many projects so it always helps to keep the planners on side.   NR will invoke it permitted development rights if it has too.

Like all large undertakings and utilities NR has a consents team that deal with local Authorities, other external railways, utilities, etc 

[johoare]

They are replacing a road bridge over the railway in Maidenhead as part of this.. I still can't understand how they are doing this whilst trains are running underneath.. Though I'm terribly impressed that they are...

I've been reliably informed by my son (who has to walk over the replacement temporary footbridge each day) that the old bridge has finally gone..

I am guessing adding the new improved, and higher bridge will also have to be done very carefully :-)

[Electric train]

They are replacing a road bridge over the railway in Maidenhead as part of this.. I still can't understand how they are doing this whilst trains are running underneath.. Though I'm terribly impressed that they are...

I've been reliably informed by my son (who has to walk over the replacement temporary footbridge each day) that the old bridge has finally gone..

I am guessing adding the new improved, and higher bridge will also have to be done very carefully :-)

Not all of it is actually done while the trains are running, some lighter work might be done behind scaffold screening or back from the open line; however the heavy lift stuff is done during an "All Line Block" type possession.

"All Line Block" type possession are like hens teeth and will have been in the planning for at least 2 years.

[NickB]

There goes the road bridge at Cox Green.... (went last Sunday apparently)

http://www.maidenhead-advertiser.co.uk/News/Areas/Cox-Green/Highfield-Bridge-lifted-out-as-part-of-electrification-works-01102014.htm

[Electric train]

There goes the road bridge at Cox Green.... (went last Sunday apparently)

http://www.maidenhead-advertiser.co.uk/News/Areas/Cox-Green/Highfield-Bridge-lifted-out-as-part-of-electrification-works-01102014.htm

I'm sure they will put something back to fill the hole 

[TonyK]

That report makes it sound like the same bridge is going back - is it?

[DidcotPunter]

The bridge on the A417 at Challow Station between Didcot and Swindon was demolished this morning. Apologies for the poor quality as it was rather foggy but here are some pictures of the last girder being lifted out by Anscough's most impressive 500 tonne lift capacity crane:


Initial lift


Mid lift


Lowering the girder


Anscough 500 t crane

The plan is for the line to be handed back by 5:00am tomorrow morning and the pre-cast beams for the new bridge deck will be lifted into position next weekend.

[bobm]

One of my favourite locations for photos between Didcot and Swindon.  Hopefully the new bridge will not be too high sided to allow future expeditions there.

[DidcotPunter]

Obviously the parapets will be higher - though you should still get a good view from the approaches.

[Red Squirrel]

Can't find the plans for this one, but I see that the replacement bridge at Pearson's Brickyard (the one you see in the up direction from the platform at Bristol Porkway) has a minimum 1525mm from pavement to top of parapet - which I make about 5s 4d in old money. If this one's the same, you may have to stand on tippytoes Bobm.

[Electric train]

One of my favourite locations for photos between Didcot and Swindon.  Hopefully the new bridge will not be too high sided to allow future expeditions there.

Can't find the plans for this one, but I see that the replacement bridge at Pearson's Brickyard (the one you see in the up direction from the platform at Bristol Porkway) has a minimum 1525mm from pavement to top of parapet - which I make about 5s 4d in old money. If this one's the same, you may have to stand on tippytoes Bobm.

BS EN 50122-2 (I think its part 2 my copy is at work) "Railway applications. Fixed installations. Electrical safety, earthing and the return circuit. Provisions against the effects of stray currents caused by d.c. traction systems"  requires min height of 1820mm, I have had a couple of upset Civil Engineers at work who have had to add and extra 295mm onto their parapets

[Red Squirrel]

This seems to apply to DC^▸ (Direct Current) traction systems... are AC systems the same?

[Electric train]

This seems to apply to DC^▸ (Direct Current) traction systems... are AC systems the same?

Its probably part 1 then, I normally just work off of in house standards

[Red Squirrel]

Sorry, I wasn't testing you - I just wondered if there were different parapet height requirements for the differing characteristics of ac and dc traction supplies. More to the point, I'm 1970mm tall (pretty big for a squirrel, huh?), so whereas I can easily see over a 1525mm parapet, an 1820mm one is a bit of a stretch!

[TonyK]

Sorry, I wasn't testing you - I just wondered if there were different parapet height requirements for the differing characteristics of ac and dc traction supplies. More to the point, I'm 1970mm tall (pretty big for a squirrel, huh?), so whereas I can easily see over a 1525mm parapet, an 1820mm one is a bit of a stretch!

There's not many DC^▸ (Direct Current) systems with overhead power kit these days, not in heavy rail anyway. I am sure that whoever ruled that the gap shalleth be 1820mm had in mind every one of the seven recognised grades of bloody idiot on railways. A grade one would try to prove to his pals that you can touch the cable with a dry wooden pole, and suffer no harm, whereas a true grade seven would want to demonstrate that a stream of alcohol-enhanced urine would not conduct 25Kv as far as the todger. All these and more must  be protected from themselves and their folly.