Great Western Electrification Progress

[33Hz]

British Rail knew, very early on, that the Regional Eurostar sets wouldn't be able to do 125mph on the ECML and breathed a collective sign of relief when the Regional services were cancelled. The rebuilding we see planned today would have been needed for 125mph Eurostar services, or some other form of re-building work for the trainsets would have been needed to get round the issue.

The next question (preemptively answering it) is why Eurostar Regional sets couldn't run at 125mph on the ECML - it's all to do with pantograph uplift force, to keep the rear pantograph in contact with the OLE at 186mph, the uplift force has to be fairly aggressive, too aggressive for the wire thickness and tension on the ECML, which is why they were limited to 110mph.

The pantograph uplift force increases with speed, to combat the oscillations in the contact wire which similarly increase with speed, it's for this reason that later iterations of the BR/BW High Speed Pantograph have aerofoils, allowing uplift force to be proportional to train speed.

The generation of TGVs that went into service immediately after the Eurostar have Faiveley CX active pantographs that use pneumatic actuators to change the pressure on the contact wire. They are designed to combat exactly this problem (there are several classic lines in France where trains travel at a range of speeds up to 140 mph). These were in use before time was called on the Regional Eurostar project, so surely the worst case scenario would have been a retrofit of such pantographs?

http://www.faiveleytransport.com/sites/default/files/lekov/datasheet/FAV_CX_v2.pdf

 

[Philip Phlopp]

The generation of TGVs that went into service immediately after the Eurostar have Faiveley CX active pantographs that use pneumatic actuators to change the pressure on the contact wire. They are designed to combat exactly this problem (there are several classic lines in France where trains travel at a range of speeds up to 140 mph). These were in use before time was called on the Regional Eurostar project, so surely the worst case scenario would have been a retrofit of such pantographs?

http://www.faiveleytransport.com/sites/default/files/lekov/datasheet/FAV_CX_v2.pdf

I'd expect the most likely solution would have been to fit a second 25kV pantograph for UK operation, possibly on the leading powered coach.

It's possible they might have fitted the Faiveley pantograph with its variable uplift, but the difficulty in getting a new pantograph approved for use in the dark days of pre privatisation British Rail and newly formed Railtrack would have almost certainly resulted in the easier approach of providing a second BR/BW High Speed pantograph.

 

[snowball]

Press release on track lowering at Dundas Aqueduct, including a link to a video. It also includes the first proper explanation of what's happening there and why.

It even expects the reader to understand what "cascaded" means. I suppose some might imagine it has something to do with the water pouring off the aqueduct.

http://www.networkrailmediacentre.c...s-track-lowering-work-through-dundas-aqueduct

 

[WelshBluebird]

Found it quite odd passing through Box on Saturday and crossing over the line to see one of the two lines totally removed. Can't say I have seen that before and even that gave me an idea of the scale of the work going on (kind of understandable considering how long the closure east of Bath is for).

 

[Envoy]

BBC Points West (Bristol) will have a report in their programme (6.30pm) about the works in the Bath area. Wednesday 19th August 2015.
If out of region >
Sky = 966.
Freesat = 965.

 

[HowardGWR]

BBC Points West (Bristol) will have a report in their programme (6.30pm) about the works in the Bath area. Wednesday 19th August 2015.
If out of region >
Sky = 966.
Freesat = 965.

Gosh, thanks, but that does annoy me. The commercial chaps can give me the local Bristol news I am interested in (and where it all happens in the SW), but the BBC via set top box, whose programme it is, - can't. I have to put up with Plymouth. Their news is just about bl**dy badgers and foxes -oh and bl**dy fish. :-x

 

[Hophead]

Just a quick question, and apologies if I've not paid full attention, or posted in the wrong thread.....

We are assured that 387s will, next Spring, operate a Paddington - Hayes service in place of the Greenford shuttle. This will release a small number of units (2, maybe 3?). Does anybody know the plan for these? Is it Thames Valley strengthening, adding to the general pool, or is a mini-cascade in prospect?

 

[snowball]

Gosh, thanks, but that does annoy me. The commercial chaps can give me the local Bristol news I am interested in (and where it all happens in the SW), but the BBC via set top box, whose programme it is, - can't. I have to put up with Plymouth. Their news is just about bl**dy badgers and foxes -oh and bl**dy fish. :-x

http://www.bbc.co.uk/iplayer/episode/b0663crx/bbc-points-west-18082015

Rail item at the beginning of the programme, but it's mostly about fares. There's a clip from the video I linked five posts up. More promised for tomorrow.

 

[hassaanhc]

Just a quick question, and apologies if I've not paid full attention, or posted in the wrong thread.....

We are assured that 387s will, next Spring, operate a Paddington - Hayes service in place of the Greenford shuttle. This will release a small number of units (2, maybe 3?). Does anybody know the plan for these? Is it Thames Valley strengthening, adding to the general pool, or is a mini-cascade in prospect?

It might not even release any units. The Greenford service currently uses 2 units, both 2-car ones as the platforms are very short. Running time for the current service is approximately 25 minutes, with 4 minutes turnaround at Paddington and 7 minutes at Greenford.
The time currently given between West Ealing and Greenford is 14 minutes in the down direction, and 11 minutes for up trains, leaving just 5 minutes total for turnaround if keeping a clockface 2tph service with a single unit. The 14 minutes would need to be reduced in order to make things less tight with a single unit.

 

[Hophead]

It might not even release any units. The Greenford service currently uses 2 units, both 2-car ones as the platforms are very short. Running time for the current service is approximately 25 minutes, with 4 minutes turnaround at Paddington and 7 minutes at Greenford.
The time currently given between West Ealing and Greenford is 14 minutes in the down direction, and 11 minutes for up trains, leaving just 5 minutes total for turnaround if keeping a clockface 2tph service with a single unit. The 14 minutes would need to be reduced in order to make things less tight with a single unit.

Aaah, yes, I'd completely overlooked the point that the service would be truncated, rather than replaced. So: one unit out. Not much they can do with that, really.

 

[LNW-GW Joint]

The time currently given between West Ealing and Greenford is 14 minutes in the down direction, and 11 minutes for up trains, leaving just 5 minutes total for turnaround if keeping a clockface 2tph service with a single unit. The 14 minutes would need to be reduced in order to make things less tight with a single unit.

Has the new bay platform at West Ealing been built yet?

 

[swt_passenger]

Has the new bay platform at West Ealing been built yet?

I think it is in progress, but that's only based on a quick glance from a passing HST.

 

[Envoy]

Gosh, thanks, but that does annoy me. The commercial chaps can give me the local Bristol news I am interested in (and where it all happens in the SW), but the BBC via set top box, whose programme it is, - can't. I have to put up with Plymouth. Their news is just about bl**dy badgers and foxes -oh and bl**dy fish. :-x

It sounds to me that you might be on the border area between SW (Plymouth) & West (Bristol). It all depends which way your aerial is pointing as to which region gets loaded on Freeview. Some people, in 'border' areas have 2 aerials - each facing the relevant transmitter. (A £3,50 combiner from Asda can be used to combine the 2 downloads). Mendip is the main transmitter for West region.

Anyway, if you select channel 1 (BBC 1) on your Freeview box & then go on the channel down hopper , if next you hit radio channels in the 700's, you are not able to receive another region with the aerial(s) that you have. If you can get another region, you will probably 'hit' it in the low 800's & should note down the BBC 1 & ITV 1 numbers that you pick up. (BBC 2 can be different on rare occasions & is certainly different in the UK nations).

PS. Many viewers in the West Country can also receive Welsh based channels from the Wenvoe transmitter. From 25 August, 2015 - ITV Wales goes HD. Due to this, a re-scan is necessary on this date.

 

[LNW-GW Joint]

I think it is in progress, but that's only based on a quick glance from a passing HST.

Yes, that was my impression too.
I thought it needed to be operational before the Greenford service split could happen.

 

[jimm]

It sounds to me that you might be on the border area between SW (Plymouth) & West (Bristol). It all depends which way your aerial is pointing as to which region gets loaded on Freeview. Some people, in 'border' areas have 2 aerials - each facing the relevant transmitter. (A £3,50 combiner from Asda can be used to combine the 2 downloads). Mendip is the main transmitter for West region.

Anyway, if you select channel 1 (BBC 1) on your Freeview box & then go on the channel down hopper , if next you hit radio channels in the 700's, you are not able to receive another region with the aerial(s) that you have. If you can get another region, you will probably 'hit' it in the low 800's & should note down the BBC 1 & ITV 1 numbers that you pick up. (BBC 2 can be different on rare occasions & is certainly different in the UK nations).

PS. Many viewers in the West Country can also receive Welsh based channels from the Wenvoe transmitter. From 25 August, 2015 - ITV Wales goes HD. Due to this, a re-scan is necessary on this date.

If you just want to watch a specific edition of a regional news programme shown on BBC1, they are available on iPlayer for 24 hours from shortly after 7pm on the day of transmission - the 10.25pm ones are also online. So the Points West one mentioned above should be viewable from just after seven tonight here http://www.bbc.co.uk/programmes/b006pft9

 

[davetheguard]

Gosh, thanks, but that does annoy me. The commercial chaps can give me the local Bristol news I am interested in (and where it all happens in the SW), but the BBC via set top box, whose programme it is, - can't. I have to put up with Plymouth. Their news is just about bl**dy badgers and foxes -oh and bl**dy fish. :-x

You are not alone. Here in south Oxfordshire we hear all about Southampton, sailing & boats, and almost continually, the second world war.

 

[SpacePhoenix]

If you're fairly close to a relay transmitter, it might drown out the signal from the main transmitter and not all relay transmitters broadcast all available commercial channels

 

[snowball]

[ More promised for tomorrow.

It's here:

http://www.bbc.co.uk/programmes/b0663csj

Electrification item from about 13:20 to about 16:00

 

[Andrewlong]

You are not alone. Here in south Oxfordshire we hear all about Southampton, sailing & boats, and almost continually, the second world war.

Totally agree - we call South Today "South Coast Today" for the reasons mentioned above. If you live in Oxford, there is an Oxford news. Here near Reading we get very little about the Thames Valley just Milton Keynes and the boats!

 

[Envoy]

Totally agree - we call South Today "South Coast Today" for the reasons mentioned above. If you live in Oxford, there is an Oxford news. Here near Reading we get very little about the Thames Valley just Milton Keynes and the boats!

I guess some people live in a kind of 'no-mans land' between the more major cities of London, Birmingham, Bristol & Southampton. Have you tried the ITV alternative? Viewers to Freesat can change the postcode in system set-up from that of their home to a neighbouring region if they think it will serve them better. (All BBC regions are in the 900's and all ITV regions can be tuned in). Anyway, we digress from the topic about the Great Western Electrification. www.digitalspy.co.uk offers forums where you can voice your complaints about broadcasting. (You can be sure that the powers that be are monitoring such comments - just as we can be sure that the rail industry are monitoring our comments on this site).

 

[snowball]

To bring this thread back to railways, two points:

1. Yet another press release on the works at Bath:

http://www.networkrailmediacentre.c...repare-baths-railway-line-for-electrification

Network Rail’s ‘orange army’ has entered the final and most critical stage of its work to prepare Bath’s railway line for electrification, with all work currently on schedule for the line to reopen on September 1.

After completing the installation of 11 new switches and crossings – which allow trains to move from one track to another – at Bathampton Junction, the team has started work to lower the track through the picturesque Sydney Gardens. Work also continues between Middle Hill Tunnel and Box Tunnel to lower the main line that runs from London Paddington towards the South West.

To explain more about the improvement work taking place in Sydney Gardens and to answer any questions the public may have, members of the Network Rail project team will be holding a drop-in session on Tuesday August 25 from 1.30pm to 4pm in Sydney Gardens, between the railway and The Holburne Museum.

2. Roger Ford's email preview is now out for his column in the forthcoming Modern Railways. Among other things it looks at GW versus ECML electrification costs.

 

[fv43576]

I am not fan of AC electric overhead cables because it looks horrible and it is spoil the view of countryside, but I have never mention anyone why not to fit DC third rail would be a lot cheaper and easy to set up than AC electric overhead cables.
Is there any reason why we can't have the third rail because it not design to go over 100mph? I have search on website to see if it any train have record holder go over 100 mph on third rail is the class 442 at 108mph

 

[Quakkerillo]

I am not fan of AC electric overhead cables because it looks horrible and it is spoil the view of countryside, but I have never mention anyone why not to fit DC third rail would be a lot cheaper and easy to set up than AC electric overhead cables.
Is there any reason why we can't have the third rail because it not design to go over 100mph? I have search on website to see if it any train have record holder go over 100 mph on third rail is the class 442 at 108mph

There have been talks already of converting (some of) the 3rd rail lines south of London to AC overhead, as the power supply is an issue.
You need a lot more substations to power trains, especially if (a) there are many services or (b) they are large/heavy trains, (c) draw a lot of power.

Since services here are going to be consisting of quite heavy trains, at some parts of the route quite frequently, and with trains providing power outlets and an on-board food service, this would just be too much for 3rd rail to deal with, or you'd need a huge amount of substations.

 

[metrovick001]

Much higher transmission losses with third rail @ 1500Vdc.
Substation need to be a lot closer & parallel conductors need to have a greater cross section due to the higher currents at the lower voltage.

With 25KVac you can cut transmission losses substantailly due to the reduced current at the higher voltage which is very desirable on a route such as the line from London to Bristol which is why the bean counters like the wires up in the air.
The down side being the erection of OHLE which without a shadow of a doubt is going to mess up photo locations!!

 

[AM9]

I am not fan of AC electric overhead cables because it looks horrible and it is spoil the view of countryside, but I have never mention anyone why not to fit DC third rail would be a lot cheaper and easy to set up than AC electric overhead cables.
Is there any reason why we can't have the third rail because it not design to go over 100mph? I have search on website to see if it any train have record holder go over 100 mph on third rail is the class 442 at 108mph

This has been dealt with several times before:
DC third rail is not cheaper on a 150+ mile long main line electrification because:
LV DC 3rd rail electrification is not viable for speeds above 100mph (forget one-off records)
LV DC 3rd rail costs much more on long routes where frequent feed points are required and need a lot more electric plant to convert the national grid supply to LV DC.
LV DC 3rd rail cannot provide enough current for heavy mixed freight and high speed passenger trains
LV DC 3rd rail does not cope well in frost, ice and snow conditions
LV DC 3rd rail is considered an unnecessary safety hazard for PW staff
LV DC 3rd rail on high speed long distance lines does not allow much power regenerated during braking to be used by other trains as there are often no trains in the same short sections.
HV AC OLE has none of the above disadvantages.
OK, so what are the disadvantages of OLE, well:
An additional clearance in the order of 250mm above the minimum for non-OLE powered vehicles, is required in tunnels, under bridges and other structures. This is often easier to acheive on main trunk routes where structures have been cleared to W10 standards for freight traffic. In the case of GWML, much of the route benefits from the original GWR's generous structure gauge, unlike those of the former Southern Railway lines.
So that leaves a part 3rd rail/part OLE line. There you would get the worst of both worlds, i.e. high power feed costs on the unreliable DC bits and the need for dual voltage trains throughout including freight locos.
The effect of OLE on the landscape view is a subjective opinion and not shared by everybody, and as has been said here before, Switzerland doesn't seem to have been ruined by it.

 

[ainsworth74]

Plus, has anyone ever worked out how to travel at higher speeds than 100mph and not have shoes being knocked off when coming into contact with the third-rail?

 

[AM9]

There have been talks already of converting (some of) the 3rd rail lines south of London to AC overhead, as the power supply is an issue.
You need a lot more substations to power trains, especially if (a) there are many services or (b) they are large/heavy trains, (c) draw a lot of power.

Since services here are going to be consisting of quite heavy trains, at some parts of the route quite frequently, and with trains providing power outlets and an on-board food service, this would just be too much for 3rd rail to deal with, or you'd need a huge amount of substations.

Apart form heating/air conditioning; power outlets, food prep. equipment and other 'hotel' services are a drop in the ocean of the traction power draw.
--- old post above --- --- new post below ---

Much higher transmission losses with third rail @ 1500Vdc.

A maximum nominal voltage of 750V DC is the maximum allowed on conventional 3rd rail. 1500V DC is normally OLE.

The down side being the erection of OHLE which without a shadow of a doubt is going to mess up photo locations!!

That is a matter of opinion, and not everybody wants to keep the scenery in aspic forever.
--- old post above --- --- new post below ---

Plus, has anyone ever worked out how to travel at higher speeds than 100mph and not have shoes being knocked off when coming into contact with the third-rail?

Yes of course, keep 3rd rail for metros and wire all the fast lines, that's why it is being done.

 

[metrovick001]

That is a matter of opinion, and not everybody wants to keep the scenery in aspic forever.


Fair enough!

 

[ainsworth74]

Did electrification ruin the East Coast Mainline? Or the West Coast? Or the Great Eastern? London, Tilbury & Southend?

 

[59CosG95]

Not forgetting Manchester-Sheffield-Wath?