Would we need a GWML high speed line?

[Benjwri]

It is highly likely that any new railway lines in the UK will be dominated by tunnel, with a handful of minor exceptions in those truly deep rural locations that are not national parks or AONBs or any other designation.

HS2 isn’t entirely tunnels, it is far cheaper to not use tunnels as much as possible.

For context the above proposed Exeter to Penzance at a very minimum would require a tunnel 3 times the length of the longest HS2 tunnel under Dartmoor National Park, and you obviously won’t be able to build ventilation or escape shafts in a National Park, so that’s a third tunnel and a huge extra expense to install a Channel Tunnel style ventilation system.

 

[HSTEd]

HS2 isn’t entirely tunnels, it is far cheaper to not use tunnels as much as possible.

This would be true in a world where all dissent could be crushed or swept aside. But that is not the world we live in.

The reality is that massive tunnel construction is the only way any major rail project will get built.
HS2 is already one of the most tunnel intensive inland rail projects in modern UK history, future projects will be more tunnel intensive. This trend is seen virtually everywhere without totalitarian governments.

For context the above proposed Exeter to Penzance at a very minimum would require a tunnel 3 times the length of the longest HS2 tunnel under Dartmoor National Park, and you obviously won’t be able to build ventilation or escape shafts in a National Park, so that’s a third tunnel and a huge extra expense to install a Channel Tunnel style ventilation system.

Why would you even go under the national park if we can't have ventilation shafts?

Going around (via Ivybridge and Chudley) costs you about 5km, which is about 55 seconds at 320km/h?

EDIT:

And I think it is far from clear that there would be a blanket prohibition on ventilation or escape shafts in the National Park.

 

[Benjwri]

The reality is that massive tunnel construction is the only way any major rail project will get built.
HS2 is already one of the most tunnel intensive inland rail projects in modern UK history, future projects will be more tunnel intensive. This trend is seen virtually everywhere without totalitarian governments.

Again I think the scale is being lost between some of the ideas being proposed on here, we saw earlier a tunnel from London to Reading being suggested, which would be rivaling the longest rail tunnel in the world, and most routes suggested on here would need significant tunneling with single tunnels being 3 times longer than that of HS2.

I don't think a blanket every project is tunnel intensive is not true. A lot of recent German have had a fair amount of tunneling (but still nothing as a proportion of the route compared to what is being suggested here), but recent and proposed TGV projects have managed without.

 

[The Ham]

And I think it is far from clear that there would be a blanket prohibition on ventilation or escape shafts in the National Park.

There's some people who reside here who would welcome having an escape tunnel:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

maps.app.goo.gl

Spoiler: link title

Link shows HMP Dartmoor

 

[PTR 444]

I personally believe the best option for a GWML high speed line (initially at least) would be to six-track the existing railway between Paddington and Reading. If the new tracks are built to 140mph, all IETs could use the new line, the existing fast lines could be used for a more intensive semi-fast service for Slough, Maidenhead and Twyford, while the reliefs could become exclusively used by the Elizabeth Line. This would solve a lot of capacity issues, provide more fast trains to London from Slough and remove the need to switch trains from the main to relief lines between Paddington and Reading.

 

[Esker-pades]

I personally believe the best option for a GWML high speed line (initially at least) would be to six-track the existing railway between Paddington and Reading. If the new tracks are built to 140mph, all IETs could use the new line, the existing fast lines could be used for a more intensive semi-fast service for Slough, Maidenhead and Twyford, while the reliefs could become exclusively used by the Elizabeth Line. This would solve a lot of capacity issues, provide more fast trains to London from Slough and remove the need to switch trains from the main to relief lines between Paddington and Reading.

How many houses would that demolish?

(Rhetorical question; ****ing loads is the answer)

 

[zwk500]

I don't think a blanket every project is tunnel intensive is not true. A lot of recent German have had a fair amount of tunneling (but still nothing as a proportion of the route compared to what is being suggested here), but recent and proposed TGV projects have managed without.

France and Germany have far less pressure on Land though. The particularly have less pressure from individual householders pressuring MPs in vulnerable seats about 'losing the view' out of their kitchen windows.

 

[Bald Rick]

France and Germany have far less pressure on Land though. The particularly have less pressure from individual householders pressuring MPs in vulnerable seats about 'losing the view' out of their kitchen windows.

The German planning process makes our look positively rapid.

 

[zwk500]

The German planning process makes our look positively rapid.

Oh, not saying they're perfect. The joys of a federal system combined with almost permanent coalition, often at several levels of government.

 

[Irascible]

That woulds be a very magical triangle.

The B&H is a very nice hypotenuse though, and unlikely to justify much investment - or replacement. So even HSR to Bristol and then down to Exeter - would be unlikely to be quicker. Getting B&H up to 125 the whole route might be better value, but even then I'm not sure how much time is lost.

I just can't see where you'd send all these trains.

You might save a few mins straightening out some bits of the B&H, but it'd hardly be worth it. Straightening out some bits between Exeter & Plymouth would probably have a bigger yield. I haven't had cause to regularily take the B&H for some time now, when I did it was perpetually crammed - adding more capacity might help more than speed, unless you got a rare lightly loaded train it wasn't particularily pleasant. It's only 20 mins or so slower now via Bristol though iiirc ( has there been a regular service that way since the wires went up? ) and some of that has to be faffing around on either junctions or the not-so-fast route via Bath.

I eyeballed HSR to Birmingham rather than London because that direction is both slower, constrained, and the directiion all the air traffic goes - although you'd have to go all the way to Scotland to come anywhere near competing with air from the SW.

 

[Benjwri]

It's only 20 mins or so slower now via Bristol though iiirc ( has there been a regular service that way since the wires went up? ) and some of that has to be faffing around on either junctions or the not-so-fast route via Bath.

Yeah about 20mins, there are still 3 services each way that travel via Bristol and Bath in the week, more at the weekend. Think most of the time is lost around Bristol and it just be a longer route, wouldn’t say the area around Bath is that slow.

 

[TheGrew]

I'm not convinced the SWML needs an HSL. Switching electrification to 25KV, increasing line speeds, and removing or mitigating as many bottlenecks as possible (specifically Woking) are probably bigger wins, on the whole, to shave time off.
The GWML is already pretty fast and getting electrified (with bits of it already completed). If there was a greater population centre I would think an HSL would make more sense on the London-Exeter-Plymouth axis but as I say I can imagine sufficient demand to make it worthwhile.
I do agree that the line from Southampton to Bristol could do with substantial speeding up though I don't know enough to suggest how.

 

[Benjwri]

The GWML is already pretty fast and getting electrified

There is no announced plan to electrify any more of the GWML, all remaining bits were either cancelled or postponed indefinitely.

 

[cle]

It's more about capacity west of Southampton - and possibly platforming there too.

undamentally, if we have 2tph to Salisbury and 4tph to Southampton and Portsmouth - of varying stopping patterns but hopefully two fast to each - then that should be a good London service.

The issue is that you move closer, and the semi-fast routes (terminators at Basingstoke, Guildford etc) also require uplifts - but tend to be more peak/commuter in pattern. And yet they will act as local, school etc connectors too.

Other problem is that Clapham, Woking, Basingstoke, Winchester, and SAP (less so) - are all busy. It's hard to have a true fast. And would it be full? I would wager more people travel from Winchester to London than Southampton Central to London (the latter is busier but has more services to elsewhere and locally) - so would HSR be useful? Also west of Southampton is a trundle but with no easy solves - so you're not really doing much for Bournemouth and Poole.

 

[The Ham]

It's more about capacity west of Southampton - and possibly platforming there too.

undamentally, if we have 2tph to Salisbury and 4tph to Southampton and Portsmouth - of varying stopping patterns but hopefully two fast to each - then that should be a good London service.

The issue is that you move closer, and the semi-fast routes (terminators at Basingstoke, Guildford etc) also require uplifts - but tend to be more peak/commuter in pattern. And yet they will act as local, school etc connectors too.

Other problem is that Clapham, Woking, Basingstoke, Winchester, and SAP (less so) - are all busy. It's hard to have a true fast. And would it be full? I would wager more people travel from Winchester to London than Southampton Central to London (the latter is busier but has more services to elsewhere and locally) - so would HSR be useful? Also west of Southampton is a trundle but with no easy solves - so you're not really doing much for Bournemouth and Poole.

I think that if there was a HS line to Salisbury with then a link to Southampton/Bristol/Exeter (probably not all the way, just enough to get a decent service) it would allow you to bypass the congestion and allow those services remaining to be increased in frequency.

Basingstoke is likely to still be fastest going via Woking, however Andover would likely be faster via Salisbury and the new line. Which would probably mean that Salisbury/Exeter wouldn't need to go via Woking and would only get as far as Basingstoke (maybe Reading).

XC could likely be the only fast service from the South Coast to Basingstoke (giving Eastleigh a more frequent service), however could run 2tph all the time (as the Cornwall services wouldn't need to go via Reading West so frequently, enabling the increase in XC services).

Portsmouth could see some services route via the HS line however that would need a fair amount of new track from the HS line to where they could connect.

You could get a reasonable level of service, maybe something like:
- 3tph to Exeter (one continues to Plymouth/Cornwall, until the Dawlish Avoiding Line is built and then all 3 would go to Plymouth with a few going to Cornwall)
- 3tph to Southampton
- 3tph to Bristol
- 2tph to Basingstoke (stopping between Salisbury and Basingstoke)

Whilst no where near as much as HS2's 17tph that's still 11tph, before there's consideration for anything extra like routing some services to Weymouth via Yeovil.

 

[cle]

I just can't see it. I think the best case is capacity and incremental line speed (plus wiring B&H) - etc - e.g. could there be triple or quad tracking between Basingstoke and Southampton in places? Could Reading be better used as an interim SWT terminus, via the Basingstoke line (again, wires and line speed) to add some frequency... make it hourly on the semi-fast Paddington to Exeter, or at least Westbury/Frome? etc - first.

Beyond Exeter, I don't know if the demand is there or what could be done, beyond massive massive things. The local network boosts around Exeter/Devon and then latterly Cornwall are cool though.

 

[The Ham]

I just can't see it. I think the best case is capacity and incremental line speed (plus wiring B&H) - etc - e.g. could there be triple or quad tracking between Basingstoke and Southampton in places? Could Reading be better used as an interim SWT terminus, via the Basingstoke line (again, wires and line speed) to add some frequency... make it hourly on the semi-fast Paddington to Exeter, or at least Westbury/Frome? etc - first.

Beyond Exeter, I don't know if the demand is there or what could be done, beyond massive massive things. The local network boosts around Exeter/Devon and then latterly Cornwall are cool though.

It's not "really" about speed out of London, rather it's about another pair of tracks taking the longer distance services off the existing lines to create more capacity for the remaining places which wouldn't benefit from the faster line.

If you are only looking at speed then you may well look at those other things.

However (as I have pointed out when the suggestion of building the Dawlish Avoiding Line is put forwards) the problem with such line speed improvements without extra capacity out of London there's limited benefit in the extra speed, as you can't add a whole lot more people to the services.

 

[stuu]

I think that if there was a HS line to Salisbury with then a link to Southampton/Bristol/Exeter (probably not all the way, just enough to get a decent service) it would allow you to bypass the congestion and allow those services remaining to be increased in frequency.

A link to Bristol/Exeter? From Salisbury? You would need to essentially build high speed lines the rest of the way for that to make any sense.

Perhaps a new line somehow from OOC-Heathrow-Reading and then to somewhere near Whitchurch, with a branch to Winchester and another towards Devizes to connect with the B&H could work. That would give extra capacity along the GWML, extra destinations from Southampton, and miss out the slowest bit of the B&H. Bristol would be better served via the GWML and perhaps some speed increases

 

[Irascible]

However (as I have pointed out when the suggestion of building the Dawlish Avoiding Line is put forwards) the problem with such line speed improvements without extra capacity out of London there's limited benefit in the extra speed, as you can't add a whole lot more people to the services.

The Devon & Cornwall bits ( and yes if you're pedantic a bit of Somerset ) go towards Bristol-Birmingham and so forth too, so any improvements there aren't solely limited by London. The traffic that way is not insignificant too. Wiring the B&H I think should really be more about just having an electric railway - the question for me is is it more important than wiring down from Birmingham and regenerating that service.

HSR to the SW from any direction isn't happening - I think we're more likely to get functional electric shorthaul aircraft.

 

[The Ham]

A link to Bristol/Exeter? From Salisbury? You would need to essentially build high speed lines the rest of the way for that to make any sense.

Perhaps a new line somehow from OOC-Heathrow-Reading and then to somewhere near Whitchurch, with a branch to Winchester and another towards Devizes to connect with the B&H could work. That would give extra capacity along the GWML, extra destinations from Southampton, and miss out the slowest bit of the B&H. Bristol would be better served via the GWML and perhaps some speed increases

In my earlier post I did say that there would likely need to be some discussion about if there was extra track beyond Salisbury.

To Bath would require an average speed of 125mph from London to get a marginally faster journey time (1:00 vs 1:20), you could possibly get could probably get close to that (and speed up the Exeter services too) by having a HS or near HS line to Westbury.

If you assume an average speed of 180mph then London Salisbury would be 30 minutes, then for the rest of the way you'd need to average 84mph. Whilst the current services take about an hour (42mph) they are stopping services, so average line speed is likely around 60mph. To Westbury if we assumed 100mph average running would probably be enough to allow for the rest of the way being slower.

To Exeter (with the above speed increases) could be about 30 minutes faster than currently.

However even the stopping service to Exeter via Yeovil (having run fast to Salisbury) would be about 2:30 and so wouldn't be all that much slower than the current GWR services (circa 2:05).

However, chances are you'd look at doubling more of the WofE line so you could run a local service (stopping Exeter to Basingstoke, maybe onto Waterloo), which could allow you to increase line speeds and skip past some of the smaller stations.

Combined, and assuming a departure time of between the 2 via Westbury services, it could possible to leave London after the faster service and still arrive before the next one arrived.

 

[cle]

However, chances are you'd look at doubling more of the WofE line so you could run a local service (stopping Exeter to Basingstoke, maybe onto Waterloo), which could allow you to increase line speeds and skip past some of the smaller stations.

It feels to me like full doubling of that route might be a smart thing to do, if increases were coming.

I've heard tell of Exeter-Honiton increases, more services out of Reading in that direction (makes sense re DMUs and compensating the Waterloo-Bristol type services) - and faster services to Salisbury and Exeter.

That said, speeding up the B&H (with wires) could also be very useful for Exeter journeys.

 

[zwk500]

It feels to me like full doubling of that route might be a smart thing to do, if increases were coming.

I've heard tell of Exeter-Honiton increases, more services out of Reading in that direction (makes sense re DMUs and compensating the Waterloo-Bristol type services) - and faster services to Salisbury and Exeter.

That said, speeding up the B&H (with wires) could also be very useful for Exeter journeys.

Wires to Exeter from Bristol Parkway and Newbury (via Taunton) is the most sensible next step. Line Speed uplift on the B&H is of doubtful help, although shorter headways might make the speed increases worthwhile but that gets very expensive.
I'd put wiring through to Plymouth above any secondary routes to Exeter though.

 

[irish_rail]

Wires to Exeter from Bristol Parkway and Newbury (via Taunton) is the most sensible next step. Line Speed uplift on the B&H is of doubtful help, although shorter headways might make the speed increases worthwhile but that gets very expensive.
I'd put wiring through to Plymouth above any secondary routes to Exeter though.

Agreed. Doing something about the very slow Plymouth to Exeter stretch should be a priority. Its quicker by road. I've been told 75mph would be very doable for most of the 60mph sections and in some cases more like 90mph. Electrification would be great as the 802s would just fly up Hemerdon, Rattery, Dainton etc. Though I doubt this part of the world would ever qualify for the amount of money needed to erect the masts etc. If only we were oooop north!

 

[Brubulus]

Agreed. Doing something about the very slow Plymouth to Exeter stretch should be a priority. Its quicker by road. I've been told 75mph would be very doable for most of the 60mph sections and in some cases more like 90mph. Electrification would be great as the 802s would just fly up Hemerdon, Rattery, Dainton etc. Though I doubt this part of the world would ever qualify for the amount of money needed to erect the masts etc. If only we were oooop north!

If the general speed on that line was raised to 90, with reductions where necessary, that seems like a good balance between speed, maintainance costs and pathing. There would need to be a few 70s on the tightest curves. The 80x won't need electrification as the dissels are pretty good up to 100mph.

 

[cle]

Wires to Exeter from Bristol Parkway and Newbury (via Taunton) is the most sensible next step. Line Speed uplift on the B&H is of doubtful help, although shorter headways might make the speed increases worthwhile but that gets very expensive.
I'd put wiring through to Plymouth above any secondary routes to Exeter though.

Have to say, I am not very familiar with the Exeter-Plymouth section - other than the obvious. Could wires along Dawlish be ok?

I think Bristol Parkway to Bristol now only really makes sense with more wiring associated - either up to Bromsgrove, or meeting wires at Taunton. But in isolation, now that the super-fasts have gone, and the re-instated platforms at Temple Meads (sadly) - it doesn't really do much by itself or free anything up.

Chippenham-TM has to be a far higher priority now. Solid 2tph and the main route, still, into Bristol from London

 

[mangyiscute]

And Didcot to Oxford is an absolute must imo - can then send 8 car 387s to oxford which provide more capacity on this route which doesn't need intercity style stock for a sub hour journey and extend the didcot stoppers to oxford too (im sure some more 387s or similar can be sourced from somewhere), which will then release more 165s and 80xs for use elsewhere on the network. For something that isn't too long and I don't think would be too complicated for such great benefits, I'm personally shocked that it isn't top of the schedule

 

[zwk500]

Have to say, I am not very familiar with the Exeter-Plymouth section - other than the obvious. Could wires along Dawlish be ok?

From what I can see on the cab view

, it broadly breaks down into 3 sections: Exeter-Dawlish is OK, the SDR Sea Wall has problematic tunnels and concerns over the cliff stability, then Teignmouth to Newton Abbot is OK, with Newton Abbot to Plymouth needing rather a lot of work.

I think Bristol Parkway to Bristol now only really makes sense with more wiring associated - either up to Bromsgrove, or meeting wires at Taunton. But in isolation, now that the super-fasts have gone, and the re-instated platforms at Temple Meads (sadly) - it doesn't really do much by itself or free anything up.
Chippenham-TM has to be a far higher priority now. Solid 2tph and the main route, still, into Bristol from London

I think it would make sense to do Parkway-Temple Meands + St Philips Marsh as the first stage of Chippenham-Bath-Bristol.

 

[irish_rail]

If the general speed on that line was raised to 90, with reductions where necessary, that seems like a good balance between speed, maintainance costs and pathing. There would need to be a few 70s on the tightest curves. The 80x won't need electrification as the dissels are pretty good up to 100mph.

The diesels are pretty good upto about 60mph , not 100. But importantly the 80x are not good hill climbers. Considerably slower up the gradients than a HST and even more so If an engine is out. They only attain class 153 speeds (i kid you not) at the top of Hemerdon bank if one engine is out (a common occurence). On electric they'd absolutely fly.

 

[snowball]

Have to say, I am not very familiar with the Exeter-Plymouth section - other than the obvious. Could wires along Dawlish be ok?

They work on the Ayrshire coast.

 

[irish_rail]

They work on the Ayrshire coast.

Too be fair staying diesel as far as Newton Abbot would be fine, maybe go over to electric somewhere in the Newton vicinity as far as Plymouth. This would take advantage of the electrics on the hilly sections , and the slower speed bit that could do with improving.