Great Western Main Line electrification - ongoing discussion

[whole diary]

[SandTEngineer]

I think I read somewhere that the gantries they're using are of a design that's rather like a Meccano  set - lots of standard parts that bolt together differently to suit the location / needs of each gantry.  And I recall that was said to make the electrification works a lot easier, cheaper and faster rather than having to do a 'special' at each location.  It struck me, though, that this could mean a certain amount of excess / needless metalwork providing attachment points for things not attached, and perhaps rather chunkier / heavier elements than were always needed as it would have to be manufactured to match worst case use scenario.   

Did I get this right, or was I having a "funny" dream??

The NR^» (Network Rail - home page) Series 1 25kv overhead electrification system is indeed designed as a kit of parts that can be selected to make up what is required at each site.  So far, in my travels around, I have not noted any bespoke components.  Personally, I don't think its that bad compared with some of the 1950s designs used for the 1500v DC^▸ (Direct Current) overhead electrification schemes (as used on the Woodhead and original Great Eastern schemes).

Perhaps ET can respond in a bit more detail?

[lordgoata]

I don't think anyone (with the possible exception of Jeremy Corbyn/the RMT^▸ (National Union of Rail, Maritime & Transport Workers)/ASLEF^» (Associated Society of Locomotive Engineers and Firemen - about)) is seriously suggesting a return to a medieval idyll/or a time when dinosaurs walked the Earth, just that perhaps a little more thought could have been given to the surrounding environment when these gantries were designed/chosen?

This issue, ultimately, is all of NR^» (Network Rail - home page)'s own making. They have freely and openly admitted they did not follow the rules for the development through an AONB^▸ (Area of Outstanding Natural Beauty), so now they are getting jumped on.

Those complaining (RAG^▸ (Radstock Action Group) and both the conservation boards) are just as bad and equally to blame. Rather than engaging with NR at the start to ensure the rules were being followed, they waited until structures were going up and then kicked off about it. Heck the two conservation boards didn't even seem to care until RAG was formed and they all grouped together!

I've only lived in Goring since 2008, but its clear they are a funny old bunch and pretty split down the middle on these things. The fuss over Tesco taking over the pub, over HSBC closing, over the house that appeared on Streatley Hill, over the Goring Lock Hydro-Electric scheme, over the parking down Streatley High Street, over the SOHA development in Cleeve, over the electrification, over the lifts at the station, over the 200+ houses that have to be developed .... they are pretty much always 50/50 for and against and it's just those against that seem to shout loudest...

[JayMac]

I think that's true of any smallish community. Always wanting things preserved in aspic and no consideration of future generations.

[BerkshireBugsy]

I think that's true of any smallish community. Always wanting things preserved in aspic and no consideration of future generations.

I agree. I lived in a small Oxfordshire village for 20 years and don't think it changed too much from the day we moved there to the day I moved out.

Had the Banbury to Cheltenham line survived it would be interesting to know how communities along the line would have reacted had the line been electrified.  Although some communities slightly north are having to deal with the possible threat of HS2^▸ (The next High Speed line(s)) passing through their unspoilt countryside

[TaplowGreen]

I think that's true of any smallish community. Always wanting things preserved in aspic and no consideration of future generations.

............rather like those in Sipson, Harmondsworth etc objecting to Heathrow expansion I guess? 

[grahame]

I think that's true of any smallish community. Always wanting things preserved in aspic and no consideration of future generations.

Hmmm ...I think we would be very happy to have wires strung up just above the track ...



... but then we're the fourth largest urban area in Wiltshire, so I suppose "smallish" isn't the word to use.  And the line connects no.s 1,2,3 and 4 in terms of size (Chippenham, Salisbury, Trowbridge and Melksham) so electrification in the next phase or two might not be such a silly idea!

[didcotdean]

Television reception isn't as good as it might have been in parts of Oxfordshire (north in particular) because the mast at Beckley is about 100 metres shorter than originally planned as a result of objections.

[Electric train]

I think I read somewhere that the gantries they're using are of a design that's rather like a Meccano  set - lots of standard parts that bolt together differently to suit the location / needs of each gantry.  And I recall that was said to make the electrification works a lot easier, cheaper and faster rather than having to do a 'special' at each location.  It struck me, though, that this could mean a certain amount of excess / needless metalwork providing attachment points for things not attached, and perhaps rather chunkier / heavier elements than were always needed as it would have to be manufactured to match worst case use scenario.   

Did I get this right, or was I having a "funny" dream??

The NR^» (Network Rail - home page) Series 1 25kv overhead electrification system is indeed designed as a kit of parts that can be selected to make up what is required at each site.  So far, in my travels around, I have not noted any bespoke components.  Personally, I don't think its that bad compared with some of the 1950s designs used for the 1500v DC^▸ (Direct Current) overhead electrification schemes (as used on the Woodhead and original Great Eastern schemes).

Perhaps ET can respond in a bit more detail?

Most OLE^▸ (Overhead Line Equipment, more often "OHLE") electrification schemes have worked from a standard design range, the 1500V dc GE and Woodhead were a BICC design some of that would have been licenced from the likes of ASEA, Brown Boveri etc, later in the 1950 with adoption of "industrial frequency" ie 50Hz ac quite a lot of French design was adopted.  BR^▸ (British Rail(ways))'s principle OLE contractors through the 1960, 70, 80 were BICC (Balfour Beatty) and Pirelli with BR hold 50% of the licence for the standard components there by allowing interchangeability, the range today is called OLEMI^▸ (Overhead Line Equipment Master Index)   

There are a number of things that have governed the GWEP^▸ (Great Western Electrification Program) OLE design. 

The requirement to improve reliability of the OLE over the Mk3 (headspan as per ECML^▸ (East Coast Main Line)) by making it IMR (Independently Mechanically Registered)
Built for a future line speed of 140mph
TSI (interoperability) compliance.
Compliance with BS EN 50122 electrical clearances, especially the case in public accessible areas.
Standardised design of structures.

The GWEP structures look and are very substantial they have a life expectance of 100 years, also to achieve the TSI and future line speed the structures are closer together typically 50 meters where as the ECML is typically 70 meters

[TonyK]

The usual comprehensive and easily understood explanation from ET - always appreciated.

[Surrey 455]

I think that's true of any smallish community. Always wanting things preserved in aspic and no consideration of future generations.

............rather like those in Sipson, Harmondsworth etc objecting to Heathrow expansion I guess? 

There is a difference. The overhead line structures are being put up above existing railway lines (obviously). Heathrow want to demolish houses and communities to get a third runway. Those who want that runway at Heathrow have no consideration for future generations who will be affected by noise both in London and Berks / Bucks / Surrey. New flight paths will come into force for that runway that will inconvenience residents previously not affected.

[Electric train]

I think that's true of any smallish community. Always wanting things preserved in aspic and no consideration of future generations.

............rather like those in Sipson, Harmondsworth etc objecting to Heathrow expansion I guess? 

There is a difference. The overhead line structures are being put up above existing railway lines (obviously). Heathrow want to demolish houses and communities to get a third runway. Those who want that runway at Heathrow have no consideration for future generations who will be affected by noise both in London and Berks / Bucks / Surrey. New flight paths will come into force for that runway that will inconvenience residents previously not affected.

And Taplow will become part of the flight path for the expanded Heathrow.

There is always objections at first to OLE^▸ (Overhead Line Equipment, more often "OHLE") structures when first installed, they are bright galvanised, not a natural shape and new on the horizon, the zinc will tarnish to a dull grey which helps to camouflage them into the skyline.  Painting them green never works because a square box shape that is green sticks out like a sore thumb more so than grey.  Whilst there is a visual impact when the new trains start to run the noise level diminishes because there is no infernal combustion engine

[BerkshireBugsy]

<Snip>

There is always objections at first to OLE^▸ (Overhead Line Equipment, more often "OHLE") structures when first installed, they are bright galvanised, not a natural shape and new on the horizon, the zinc will tarnish to a dull grey which helps to camouflage them into the skyline.  Painting them green never works because a square box shape that is green sticks out like a sore thumb more so than grey. 

I agree - in my post of a few minutes ago (see below) I have drawn the comparison between this and the Newbury bypass that was in the news 20 years ago.

http://www.firstgreatwestern.info/coffeeshop/index.php?topic=16626.0

[broadgage]

The OHLE^▸ (Over-Head Line Equipment (electrification via catenary)) used on the East coast route is in my view less visually obtrusive than that currently being installed in the West.
I would however observe that the East coast scheme seems to fail regularly in even moderately windy weather, and I would hope that the more robust looking structures being installed at present will be reliable.

[Electric train]

The OHLE^▸ (Over-Head Line Equipment (electrification via catenary)) used on the East coast route is in my view less visually obtrusive than that currently being installed in the West.
I would however observe that the East coast scheme seems to fail regularly in even moderately windy weather, and I would hope that the more robust looking structures being installed at present will be reliable.

The system on the ECML^▸ (East Coast Main Line) (and HEX on the GWML^▸ (Great Western Main Line)) is known as Headspan it was part of BR^▸ (British Rail(ways))'s Mk3 OLE^▸ (Overhead Line Equipment, more often "OHLE") range.   

Its main vulnerability is the across track wire support spans, when there is a di-wirement of the contact wire on one road there is a tendency for the contact wire on all other roads to get displaced prevent trains from running, even non electric because the wire can foul gauge.  GWEP^▸ (Great Western Electrification Program) has adopted independent mechanical registration.  Also they have adopted electrical separation between Main Lines and Relief Lines to allow for safe maintenance
Blow off due to high wind speed on the ECML is in part due to the spacing of the OLE support structures typically 70 meters GWEP the spacing is closer to 50 meters.  20 meters may not sound much but over 194 km (120) miles that's a lot of extra cost

[ellendune]

New Network Rail time lapse video of Stratton Green Bridge works over Christmas available via the Swindon Advertiser