Great Western Electrification Progress

[jyte]

I have a question that was raised following the 387 thread about the feed in points (national grid connections).

Does the program need all four feed in points (Kensal Green/Didcot/Melksham and Cardiff) to be operational in order to function or could it get away with operating with only 3 or even 2?

I'm presuming if the grid connections at Didcot and Melksham both failed you'd loose electric train services over most of the line.

 

[swt_passenger]

I have a question that was raised following the 387 thread about the feed in points (national grid connections).

Does the program need all four feed in points (Kensal Green/Didcot/Melksham and Cardiff) to be operational in order to function or could it get away with operating with only 3 or even 2?

I'm presuming if the grid connections at Didcot and Melksham both failed you'd loose electric train services over most of the line.

There will be reversionary modes, the midpoint autotransformer feeder stations include switchgear to feed between adjacent sections. It would be unlikely to provide for full scale normal operations though, more likely a means to run a half service or something like that.

 

[GRALISTAIR]

Does the program need all four feed in points (Kensal Green/Didcot/Melksham and Cardiff) to be operational in order to function or could it get away with operating with only 3 or even 2?

I'm presuming if the grid connections at Didcot and Melksham both failed you'd loose electric train services over most of the line.

There will be reversionary modes, the midpoint autotransformer feeder stations include switchgear to feed between adjacent sections. It would be unlikely to provide for full scale normal operations though, more likely a means to run a half service or something like that.

Highly unlikely two would fail at once. If 1 fails they will still be able to run a half decent service. If the Swansea extension does not happen there will be spare current capacity at Cardiff. Similar argument for Oxford - Didcot.

 

[coppercapped]

I have a question that was raised following the 387 thread about the feed in points (national grid connections).

Does the program need all four feed in points (Kensal Green/Didcot/Melksham and Cardiff) to be operational in order to function or could it get away with operating with only 3 or even 2?

I'm presuming if the grid connections at Didcot and Melksham both failed you'd loose electric train services over most of the line.

Historically feeder points using the 132kV supplies used a minimum of two transformers at each site each feeding a section of OHLE leading away from the feeder point. The two circuits could be connected together if one of the transformers failed or needed maintenance but they were normally isolated. This meant that the chances any feeder point could fail completely was very remote.

I have not seen circuit diagrams for the 400kV/25-0-25kV autotransformer feeder stations (ATFS), such as the ones at Kensal Green and Didcot, but I would presume the use of two transformers would still be normal.

So the only power supply failure mode which would knock out a complete ATFS would be if the 400kV grid supply failed. Considering the grid is essentially an enormous ring main any point can be supplied from either side. How often does the 400kV grid fail? I have no statistics, but judging by the number of times my house is plunged into blackness - not very often!

 

[JN114]

HOPS and conventional wiring taking place at/around Twyford this evening; HOPS was working in the Down Main platform running one of the wires (I wasn't paying enough attention to which). Conventional wiring/OHLE work was taking place at both Waltham and Ruscombe; and also a small worksite country side of Lands End Crossovers.

 

[3973EXL]

Few pictures from this morning.

View from Southbury Lane bridge showing mains wired the other week.
Parapet progress at Twyford.
Two view of the DM, first wires through a platform at Twyford.

Short section wired from MP30 3/4 to just off the Reading end of the platform last night. About 1/2 mile on the DM left to wire to link up at Twyford West.

 

[jyte]

Few pictures from this morning.

View from Southbury Lane bridge showing mains wired the other week.
Parapet progress at Twyford.
Two view of the DM, first wires through a platform at Twyford.

Short section wired from MP30 3/4 to just off the Reading end of the platform last night. About 1/2 mile on the DM left to wire to link up at Twyford West.

Great photos as usual, thank you.

 

[jimm]

Some pictures of steelwork up at Compton Beauchamp (just east of Shrivenham) the weekend before last taken by Martin Loader are here http://hondawanderer.com

Scroll down past the Chiltern Class 121s on their last day in service.

 

[3973EXL]

Two HOPS trains working last night.
DM extent of OHL from Padd now west end of Twyford station. In other words the gap at Maidenhead was wired.
Also UM wired through Twyford station, same as DM the night before.

 

[3973EXL]

Two HOPS trains working last night.
DM extent of OHL from Padd now west end of Twyford station. In other words the gap at Maidenhead was wired.
Also UM wired through Twyford station, same as DM the night before.

Three pictures of the new wires at Twyford.

Other shots around MP32 - Lands End bridge and the west end of the Twyford west ladder.
Wire details and view towards Reading.

 

[davetheguard]

Thanks for the Twyford pictures, 3973EXL.

I don't suppose you know if the facing crossover between the Up & Down Relief at the London end of Twyford station is being electrified too, do you? In the early to mid 80's this crossover used to be used every night by the empty DMU off the Henley branch to return to Reading depot.

I wonder if it still sees any regular use, because later the signalling was changed so that it was possible to run direct from the Up Relief platform at Twyford towards Reading, crossing to the Down Relief Line at Lands End Junction (aka Twyford West). In fact this change facilitated the regular off peak Henley to Reading through train service that ran for a few years (in the late 80's / early90's?).

 

[3973EXL]

Thanks for the Twyford pictures, 3973EXL.

I don't suppose you know if the facing crossover between the Up & Down Relief at the London end of Twyford station is being electrified too, do you? In the early to mid 80's this crossover used to be used every night by the empty DMU off the Henley branch to return to Reading depot.

I wonder if it still sees any regular use, because later the signalling was changed so that it was possible to run direct from the Up Relief platform at Twyford towards Reading, crossing to the Down Relief Line at Lands End Junction (aka Twyford West). In fact this change facilitated the regular off peak Henley to Reading through train service that ran for a few years (in the late 80's / early90's?).

Crossover in this picture.

Look to me as if the masts and registration arms are in place for the wires.

Used by the down Padd to Henley thro trains, so would have been planned to be done. Would seem pointless not to do it, even if the branch is on hold.

I'll try and get a better picture next time I'm there.

 

[Wilts Wanderer]

It is also used on Saturday nights when the last few trains from Paddington terminate at Twyford.

 

[Mintona]

I used it on an HST a few months back. I'm certain it will be electrified.

 

[II]

It won't see as much use with the removal of the Henley trains, but it's a bona-fide route for passengers trains on the main line (well, relief lines) so it will be wired. Useful for early morning/late evening stock movements as well as at time of disruption.

 

[Mag_seven]

I can't see many crossovers not being electrified - operationally it would be a nightmare. When they originally electrified Edinburgh Waverly for the ECML they penny pinched and didn't electrify the central mound tunnels - an electric hauled train got signalled through them and became dewired.

 

[3973EXL]

2 x HOPS trains out again last night.
DM is now wired to just after MP34 3/4 (nearly to Kennet bridge). Missing gag between Twyford and Twyford West was the section completed.

Other work was wiring the main to main crossover at Ruscombe.
Outstanding work on the mains (MP25 to 34 3/4) is on the UM only - gap MP25 to 25 3/4 and 1/2 gap west of Twyford. There is also a section, about 3/4 mile of catenary wire only from just before MP29.

 

[3973EXL]

2 x HOPS trains out again last night.
DM is now wired to just after MP34 3/4 (nearly to Kennet bridge). Missing gag between Twyford and Twyford West was the section completed.

Other work was wiring the main to main crossover at Ruscombe.
Outstanding work on the mains (MP25 to 34 3/4) is on the UM only - gap MP25 to 25 3/4 and 1/2 gap west of Twyford. There is also a section, about 3/4 mile of catenary wire only from just before MP29.

Photos are: newly wired section on the DM meets existing wires at Twyford West.
DM over Loddon viaduct.
Mains West end of Twyford station x 2.

For information, the situation on the reliefs MP25 to MP34 3/4 as far as I know:
UR/DR gap at Maidenhead MP25 to 25 3/4.
gap just before MP29 to west end of Loddon viaduct after MP31 1/2.
DR has a section of catenary wire only at the west end of Sonning cutting.

Twyford West: main to relief part of the crossovers to wire.
Kennet Loop to wire.

Reading Pl 10 still requires contact wire.

 

[3973EXL]

Crossover in this picture.

Look to me as if the masts and registration arms are in place for the wires.

Used by the down Padd to Henley thro trains, so would have been planned to be done. Would seem pointless not to do it, even if the branch is on hold.

I'll try and get a better picture next time I'm there.

Twyford East relief crossover.

 

[davetheguard]

Twyford East relief crossover.

That's the one! Good to see it still being in use, and electrified. I don't know how, but somehow I had forgotten that the through Padd to Henley trains would need to use it to cross from the Down Relief Line to the Up Relief platform, prior to running on to the branch line itself.

Thanks for the pictures.

 

[jyte]

Question : January 2018 is the Maidenhead-Didcot in customer use target, correct?

How soon are the wires here likely to be complete?

 

[jimm]

Overhead wires now in place near Wantage - some pictures taken by Martin Loader at Denchworth on Thursday are here.

http://hondawanderer.com/Recent_Additions.htm

 

[DidcotDickie]

Overhead wires now in place near Wantage - some pictures taken by Martin Loader at Denchworth on Thursday are here.

http://hondawanderer.com/Recent_Additions.htm

HOPS train was working at Challow Station this morning when I went past. Down main appears to be wired fully from west of Wantage Road to Baulking, though there may be a short gap west of Challow. Down relief is wired from Wantage Road to Denchworth. From Martin Holder's pics it looks like some of the up relief is now wired too. At Wantage Road the unwired OLE now has small part steelwork fitted.

 

[DidcotDickie]

Question : January 2018 is the Maidenhead-Didcot in customer use target, correct?

How soon are the wires here likely to be complete?

I've read elsewhere that August 2017 is the target for completion of the wiring, though I've not seen anything confirmed officially.

At the current rate of progress this should be easily achievable. Would also allow plenty of time for testing before introducing the class 387s and 800s on AC through to Didcot.

 

[Dr Hoo]

I can't see many crossovers not being electrified - operationally it would be a nightmare. When they originally electrified Edinburgh Waverly for the ECML they penny pinched and didn't electrify the central mound tunnels - an electric hauled train got signalled through them and became dewired.

Whilst not spending any amount of money could be described as 'penny pinching' it is worth appreciating that the 'quick' decision not to wire the Central bore of the Mound tunnel by British Rail in 1990/1 was down to the fact that it would have required the lowering of the entire western throat of Edinburgh Waverley, including the platform ends. When Waverley was fully upgraded, with the additional platforms and general re-modelling for the Airdrie-Bathgate electrification and other schemes, the work was planned over a far longer period and its execution was very disruptive to Edinburgh passengers at the time. (A lot more so than the occasional dewirement!)

 

[mathmo]

The first wires are now up in the MP25 gap. The Down Main now has catenary and contact wires, plus a return wire (is that right?). I can't see if it goes all the way through the gap but hopefully someone can confirm soon.

 

[NotATrainspott]

Whilst not spending any amount of money could be described as 'penny pinching' it is worth appreciating that the 'quick' decision not to wire the Central bore of the Mound tunnel by British Rail in 1990/1 was down to the fact that it would have required the lowering of the entire western throat of Edinburgh Waverley, including the platform ends. When Waverley was fully upgraded, with the additional platforms and general re-modelling for the Airdrie-Bathgate electrification and other schemes, the work was planned over a far longer period and its execution was very disruptive to Edinburgh passengers at the time. (A lot more so than the occasional dewirement!)

Also worth noting is that all of these extra works would have meant absolutely no benefit to the IC225 or North Berwick electrified services. Neither had any way of using the western bay platforms. It was only for A-B electrification that there was any justification for wiring up any of the rest of the tracks. That includes the northern Haymarket tunnel which has no connection to the Carstairs line at all, but is now wired up (including Haymarket platform 0) as it is connected to the E&G via the ladder crossing west of the station.

 

[jyte]

Does anyone know the status of platform 1&2 at Paddington?

It was still unwired last time I was there (over a month ago now) but I was just wondering if anyone knows if that position has changed.

On and unrelated considering the scale of the closures this weekend, I hope the HOPS train(s) is busy!

 

[SpacePhoenix]

Once the electrification is complete, at what junction will the Plymouth/Penzance/Exeter trains leave the OLE?

 

[DidcotDickie]

Once the electrification is complete, at what junction will the Plymouth/Penzance/Exeter trains leave the OLE?

Newbury (immediately west of station) for those routed on the B&H line