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Great Western Electrification Progress

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edwin_m

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Surely, the parts of the GWR electrification to Temple Meads and to Oxford are ready to go as they were suddenly curtailed to get Cardiff wired.
Wouldn't they be subject to re-design to incorporate all the lessons from other schemes and get the costs down?
 
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Domh245

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Weren't they paused subject to major remodellings of the respective locations (Oxford & Temple Meads) meaning that in effect no designs will be shovel ready, or was that urban legend?
 

Meerkat

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Surely, the parts of the GWR electrification to Temple Meads and to Oxford are ready to go as they were suddenly curtailed to get Cardiff wired.
Temple Meads needs the junction outside to be redone. Oxford needs a decision on whether to quadruple.
 

nlogax

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Mostly Glasgow-ish. Mostly.

edwin_m

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Temple Meads needs the junction outside to be redone. Oxford needs a decision on whether to quadruple.
As I understand it the recent re-modelling at the station area includes provision for an extra platform to be added later, and possibly one or two more if the station building is demolished. If the electrification in the station area itself was designed with that in mind, there wouldn't be much re-work to add those extra platforms to the OLE if and when needed.

I don't think quadrupling Oxford to Didcot has ever been the subject of a serious study, but if it happened it would certainly render most of the electrification work already done (both design and I understand some construction) wasted.
Probably best to go with the existing design rather than incur even more costs and delay the job!
Not sure. Using slightly heavier structures than optimum might not be a big deal, especially as the two-track sections of GWML seem to be less obviously over-engineered. However it's now well known that many of the pile sizes were drastically over-designed, probably leading to extra unplanned work on site if built to current designs. Re-doing the calculations for those piles not yet installed might be worthwhile.
 

themiller

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Not sure. Using slightly heavier structures than optimum might not be a big deal, especially as the two-track sections of GWML seem to be less obviously over-engineered. However it's now well known that many of the pile sizes were drastically over-designed, probably leading to extra unplanned work on site if built to current designs. Re-doing the calculations for those piles not yet installed might be worthwhile.
If only they’d gone with single track cantilevered masts instead of twin track cantilevers. Was it a case of a fee per drawing from the designers instead of specifying a simple, repeatable design?
 

edwin_m

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If only they’d gone with single track cantilevered masts instead of twin track cantilevers. Was it a case of a fee per drawing from the designers instead of specifying a simple, repeatable design?
Isn't it mostly single track cantilevers west of Swindon? What was proposed for Didcot-Oxford?

Bedford-Kettering is nearly all TTCs and looks much more repeatable than GWML.
 

Meerkat

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I understand that Oxford is ready for wiring and that four tracking is catered for in the current layout without further modification.
I am talking about quadrupling Didcot to Oxford. Really should be a given as clearly not ideal trying to shove GWR and XC expresses, local stoppers, and a major freight artery, down two tracks.
 

Jurassicjewel

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Does anyone know if trains are running through Severn tunnel both ways on electric yet?, guess that things may be delayed a bit given the current situation?

Secondly, given that electrification is back on the agenda again, perhaps wiring from Didcot to oxford and Chippenham- Bath-Bristol- Parkway may re emerge from the deferral world.
 

mr_jrt

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I swear I read something recently about quadrupling south from Oxford as far as Abingdon as a proposal?
 

JamesT

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I swear I read something recently about quadrupling south from Oxford as far as Abingdon as a proposal?

It’s been suggested in the past that quadrupling Oxford down to Kennington Junction at least would be necessary to run services along the Cowley branch.
 

Alex27

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Certainly there are pillars already up after didcot, but they were clearly abandoned fairly rapidly, as their all in various stages of construction and there's nothing beyond appleford, aside from the occasional foundation. As far as I can remember there was only one post per gantry (It's been a few weeks scince I travelled on that stretch for obvious reasons, so don't quote me on it:s)
 

LNW-GW Joint

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Surely, the parts of the GWR electrification to Temple Meads and to Oxford are ready to go as they were suddenly curtailed to get Cardiff wired.

NR sold off the unused stock of OHLE components last year, so would have to start procurement again.
Also the cost of Series 1 was one of the factors that sank the original project.
One would expect a restart on a reduced cost base would require a down-sized design, more like the Series 2 northern/Scottish projects.
None of the outstanding route needs the 140mph spec.
 

Peter Sarf

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NR sold off the unused stock of OHLE components last year, so would have to start procurement again.
Also the cost of Series 1 was one of the factors that sank the original project.
One would expect a restart on a reduced cost base would require a down-sized design, more like the Series 2 northern/Scottish projects.
None of the outstanding route needs the 140mph spec.

I wonder what the unused stock of Series 1 OHLE was for ?. Or was it merely spares in case of problems during construction ?.
 

Mollman

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I wonder what the unused stock of Series 1 OHLE was for ?. Or was it merely spares in case of problems during construction ?.
I think all GW was going to be Series 1 but as LNW-GW said, now your starting from scatch you would order cheaper and better looking Series 2 rather than Series 1
 

Domh245

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Not necessarily Series 2 but UKMS which uses pretty much any/everything available, including the Bonomi equipment from Series 2, capable of up to 140mph
 

themiller

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It’s not difficult to fabricate the masts given a drawing. I would estimate that a mast could be turned round in about a fortnight in normal times. It’d probably take longer than that to mobilise in the new location.
 

59CosG95

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Not necessarily Series 2 but UKMS which uses pretty much any/everything available, including the Bonomi equipment from Series 2, capable of up to 140mph
The SICAT SA range, used on Shields-Gourock' OLE renewal scheme, and the reopened Larkhall branch, has also been added in; the new OLE on the Stevenage Turnback project has cantilevers from that range.

SICAT's also been picked for Transpennine as the new masts will be shorter than they would need to be for Bonomi/Alstom equipment (as used on S2). They also allow for longer span lengths (along-track structure separation) than Bonomi/Alstom/F+F equipment; the maximum with those cantilevers is 65m, but with SICAT it increases to 74m, meaning less structures overall on plain line sections without curves.

However, all of these bits of equipment are only suitable for 125mph; while early versions of UKMS included Series 1 equipment, the drawings were never formally accepted. As a result, the Series 1 MPA Anchor Portals, the Monobooms (i.e. tensorex portals), the Q-boom portals, the hook-and-pin TTCs, and even the single telescopic Series 1 STC arms that hold the gooseneck cantilevers aren't in the range, and special bespoke derogations have to be obtained; they've done this on the MML for example.
 
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edwin_m

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However, all of these bits of equipment are only suitable for 125mph; while early versions of UKMS included Series 1 equipment, the drawings were never formally accepted. As a result, the Series 1 MPA Anchor Portals, the Monobooms (i.e. tensorex portals), the Q-boom portals, the hook-and-pin TTCs, and even the single telescopic Series 1 STC arms that hold the gooseneck cantilevers aren't in the range, and special bespoke derogations have to be obtained; they've done this on the MML for example.
So why did the MML need to use any Series 1 parts, as there's no intention of going above 125mph?
 

59CosG95

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So why did the MML need to use any Series 1 parts, as there's no intention of going above 125mph?
Most likely designers' (or contractors') preference. The Series 1 monobooms have proven very useful away from the GWML; they're used on the GOBLIN, at the new Kettering EMU Sidings, at the new Springs Branch sidings in Wigan, and even on the new temporary Tyne & Wear Metro depot in Howdon.
The mid-point anchor boom has also appeared as an anchor to tramway OLE in Ardwick depot, and also appeared just north of Bromsgrove when they put wires down the Lickey.

There is also 1 Bonomi cantilever somewhere in the Newport area, which I believe was chosen as it could handle radial loads better than the F+F one.
 

edwin_m

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Most likely designers' (or contractors') preference. The Series 1 monobooms have proven very useful away from the GWML; they're used on the GOBLIN, at the new Kettering EMU Sidings, at the new Springs Branch sidings in Wigan, and even on the new temporary Tyne & Wear Metro depot in Howdon.
The mid-point anchor boom has also appeared as an anchor to tramway OLE in Ardwick depot, and also appeared just north of Bromsgrove when they put wires down the Lickey.

There is also 1 Bonomi cantilever somewhere in the Newport area, which I believe was chosen as it could handle radial loads better than the F+F one.
Must be a pretty strong preference to justify the hassle of getting derogation and the risk of failing. I assume by "tramway overhead" you mean single wire in the Siemens/Transpennine depot - I initially thought you were referring to somewhere on Metrolink.
 

59CosG95

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Must be a pretty strong preference to justify the hassle of getting derogation and the risk of failing. I assume by "tramway overhead" you mean single wire in the Siemens/Transpennine depot - I initially thought you were referring to somewhere on Metrolink.
Yes - by 'tramway', I do indeed mean the single wire in the depot.

I recall that Atkins did the design for the MML, and the GWML too - go figure!
 

Envoy

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I just hope that they use something that is better looking between Chippenham & Temple Meads as the line passes through some very scenic countryside - plus of course, Bath.
 

LNW-GW Joint

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Probably best to go with the existing design rather than incur even more costs and delay the job!

That's what caused all the cost overrun trouble in the first place.
Oxford has at least got many of the bases from Didcot already installed (done right at the start of the GW scheme something like 8 years ago).
 

themiller

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I just hope that they use something that is better looking between Chippenham & Temple Meads as the line passes through some very scenic countryside - plus of course, Bath.
A separate design was done for, at least, going through Bath and was approved by the relevant bodies.
 
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