Where should HS3 go and why?

[TheGrew]

I think if you were going to build a 'high speed' line in the South you couldn't really justify a speed above 140mph. What I could see working is a South Eastern High Speed Arrangement with trains joining after the traditional network bottlenecks.
Something like the following: Victoria-Gatwick (probably largely tunnelled through back London to a portal near Redhill). from Gatwick trains could continue to Brighton/Eastbourne etc...

Or Waterloo-Southampton with new tunnel under Southampton possibly with a Portal somewhere near the Hedge End to allow connection to Portsmouth using the Eastleigh-Fareham line (which would need redoubling in places).

What do people think?

 

[tbtc]

I think if you were going to build a 'high speed' line in the South you couldn't really justify a speed above 140mph. What I could see working is a South Eastern High Speed Arrangement with trains joining after the traditional network bottlenecks.
Something like the following: Victoria-Gatwick (probably largely tunnelled through back London to a portal near Redhill). from Gatwick trains could continue to Brighton/Eastbourne etc...

Or Waterloo-Southampton with new tunnel under Southampton possibly with a Portal somewhere near the Hedge End to allow connection to Portsmouth using the Eastleigh-Fareham line (which would need redoubling in places).

What do people think?

I think that's a sensible comment (in the middle of various fantasy ideas about running at 250mph from Plymouth to Penzance...).

There's something to be said for a separate line through south London, taking pressure away from current bottlenecks like East Croydon - no need for a whole new "HS" line all the way to the coast though.

The danger is that I sound like I'm coming out in favour of "BML2"...

 

[The Ham]

I think if you were going to build a 'high speed' line in the South you couldn't really justify a speed above 140mph. What I could see working is a South Eastern High Speed Arrangement with trains joining after the traditional network bottlenecks.
Something like the following: Victoria-Gatwick (probably largely tunnelled through back London to a portal near Redhill). from Gatwick trains could continue to Brighton/Eastbourne etc...

Or Waterloo-Southampton with new tunnel under Southampton possibly with a Portal somewhere near the Hedge End to allow connection to Portsmouth using the Eastleigh-Fareham line (which would need redoubling in places).

What do people think?

I think that having the line running London Eastleigh (where it splits) with one part running to Poole and one part running to just north of Portsmouth with the option of a junction at Basingstoke for trains to Salisbury.

That way you could remove a number of the express services from the SWML (some to be removed all together and some by adding in a few extra stops) with a calling pattern of:
2tph London, Basingstoke, Andover, Salisbury (replaces 1tph from Salisbury)
1tph London, Farnborough, Basingstoke, Winchester, Southampton, Bournemouth, Poole, Wareham and Weymouth (replaces 1tph)
1tph London, Farnborough, Basingstoke, Winchester, Portsmouth (replaces 1tph)
2tph London, Woking, Portsmouth
2tph London, Winchester, Southampton, Bournemouth (replaces 1tph)
1tph London, Woking, Basingstoke, Southampton, Bournemouth, Poole, Wareham and Weymouth (replaces 1tph)
1tph London, Woking, Basingstoke, Winchester, Brighton

 

[philjo]

I think that's a sensible comment (in the middle of various fantasy ideas about running at 250mph from Plymouth to Penzance...).

There's something to be said for a separate line through south London, taking pressure away from current bottlenecks like East Croydon - no need for a whole new "HS" line all the way to the coast though.

The danger is that I sound like I'm coming out in favour of "BML2"...

What we need firstly is a new tunnel connecting HS2 across London - stations at Old Oak common, Euston/Kings Cross and Stratford international (probably below the current platforms.) this is for High speed services crossing London, crossrail is for the local all stations metro services.
At Stratford there would be onward connection for through running onto HS1 and onto east anglia lines and later a new HS line to Stansted/Cambridge.
At Euston/kings cross another line would branch off with one station in London - probably London Bridge for connectivity & proximity to the city and then next station would be at Gatwick Airport. This would remove the Gatwick Express services from the current route via East Croydon (or allow them to stop there and at Clapham) as the HS train would be the new express service.
using the classic compatible stock, HS services can then run from Brighton & Gatwick to Birmingham (or to Manchester airport) etc and another portion from Kent via HS1 or from East Anglia can couple at Euston or OOC.
Some other services going through the cross-London tunnel need not go on to the HS line - e.g. a new Stansted-Heathrow service.

It would reduce the number of extra platforms needed for HS2 in the main station at Euston

 

[TheGrew]

I think that having the line running London Eastleigh (where it splits) with one part running to Poole and one part running to just north of Portsmouth with the option of a junction at Basingstoke for trains to Salisbury.

That way you could remove a number of the express services from the SWML (some to be removed all together and some by adding in a few extra stops) with a calling pattern of:
2tph London, Basingstoke, Andover, Salisbury (replaces 1tph from Salisbury)
1tph London, Farnborough, Basingstoke, Winchester, Southampton, Bournemouth, Poole, Wareham and Weymouth (replaces 1tph)
1tph London, Farnborough, Basingstoke, Winchester, Portsmouth (replaces 1tph)
2tph London, Woking, Portsmouth
2tph London, Winchester, Southampton, Bournemouth (replaces 1tph)
1tph London, Woking, Basingstoke, Southampton, Bournemouth, Poole, Wareham and Weymouth (replaces 1tph)
1tph London, Woking, Basingstoke, Winchester, Brighton

That makes sense, my reason for splitting where I did was that the line from Eastleigh-Southampton Central (especially St Denys-Southampton Central) is a congestion point on the network. To a lesser extent as well the hourly Portsmouth-Eastleigh and Romsey-Eastleigh services cause the fast lines to be blocked while they traverse the points.

On a bit more of a tangent how expensive would Marshlink be to electrify. I could see a fast St Pancras-Hastings service proving popular. Line speed would have to improve on Marshlink mind you.

 

[philjo]

I suspect that building a HS line through the New Forest would not be possible without a lot more opposition than currently experienced with HS2. probably easier to send the line towards Salisbury anyway with ah spur towards Bournemouth (following the A338) - though that means not serving Southampton area.

 

[TheGrew]

I suspect that building a HS line through the New Forest would not be possible without a lot more opposition than currently experienced with HS2. probably easier to send the line towards Salisbury anyway with ah spur towards Bournemouth (following the A338) - though that means not serving Southampton area.

Agreed with your first point though I don't think added capacity is needed west of Southampton (though I am more than happy to be corrected). You have what 4TPH (2 Weymouth, 1 Poole and 1 Bournemouth CC) through the New Forest and no freight west of the junction to Hythe.

 

[HSTEd]

I think if you were going to build a 'high speed' line in the South you couldn't really justify a speed above 140mph. What I could see working is a South Eastern High Speed Arrangement with trains joining after the traditional network bottlenecks.
Something like the following: Victoria-Gatwick (probably largely tunnelled through back London to a portal near Redhill). from Gatwick trains could continue to Brighton/Eastbourne etc...

Why not?
London-Gatwick is 38km and in Japan trains equipped for 320kph running operate on such journeys. (Indeed shorter than that).
Welcome to the world of the Shinkansen and all (or nearly all)-axles motored multiple units.

140mph is pointless, you might as well not bother with the ridiculously short journey time advantages you get over 110mph.
When going high speed you have to go High speed or not at all.
You throw away journey time advantage and gain almost nothing for your trouble (your tunnelling costs don't decrease significantly in this world of TBMs and since the rolling stock is going to be bespoke classic compatible sets anyway you don't really save any money on rolling stock, and you might even need additional units to cover the longer "cycle" time).

Or Waterloo-Southampton with new tunnel under Southampton possibly with a Portal somewhere near the Hedge End to allow connection to Portsmouth using the Eastleigh-Fareham line (which would need redoubling in places).

What do people think?

Would be cheaper to build a high speed line west from Brighton roughly paralleling the path of the West Coastway.
That way you don't have to build multiple "penetrations" of inner London and its insane construction costs.

 

[185]

where should HS3 go, if it were to go ahead?

Dublin :P

 

[TheGrew]

Why not?
London-Gatwick is 38km and in Japan trains equipped for 320kph running operate on such journeys. (Indeed shorter than that).
Welcome to the world of the Shinkansen and all (or nearly all)-axles motored multiple units.

Indeed I am aware of Shinkansen and it's ridiculous acceleration.

140mph is pointless, you might as well not bother with the ridiculously short journey time advantages you get over 110mph.

But how much time on the BML or SWML is actually spent at line speed (especially inside zone 6) this is where the time savings can be made due to less congestion.

When going high speed you have to go High speed or not at all.
You throw away journey time advantage and gain almost nothing for your trouble (your tunnelling costs don't decrease significantly in this world of TBMs and since the rolling stock is going to be bespoke classic compatible sets anyway you don't really save any money on rolling stock, and you might even need additional units to cover the longer "cycle" time).

Well for stock I was thinking a 395 derivative which already exists. I don't think speed is really needed for the south coast but capacity is. Much like the fact you can slow down classic WCML services once HS2 is built you could do something similar with BML or SWML services.

 

[HowardGWR]

Dublin :P

No need for the smiley, I can see that one happening one day. Dublin Liverpool Birmingham London Paris Basel. Like it. But we do need the Railway Lords connection too.

 

[HSTEd]

But how much time on the BML or SWML is actually spent at line speed (especially inside zone 6) this is where the time savings can be made due to less congestion.

In which case why bother with 140mph?
If we are just going for the "continuous run" time savings we might as well just use the existing unit designs at 100 or 110mph.
140mph is a rather pointless half way house IMHO.

Well for stock I was thinking a 395 derivative which already exists. I don't think speed is really needed for the south coast but capacity is. Much like the fact you can slow down classic WCML services once HS2 is built you could do something similar with BML or SWML services.

Speed might not be needed but it is very useful.
Think of the times elsewhere on the network where huge amounts are spent to save a handful of seconds or minutes.

Time saved on the high speed section means that a wider range of journeys can practically use it.
A line to brighton at 320kph gets you capacity relief all the way out to Portsmouth.

 

[Rational Plan]

1st you need Crossrail 2, then a new express tunnel from Wimbledon to Woking and then as far congestion on the existing line justifies. A new express line as far as Southampton seems justified. There is talk of reviving the old SWML express route around Southampton, with a new line going through the suburban towns North of Bournemouth.

I'm sure both routes would attract new traffic, drawing it away from existing routes.

The new high speed line could be London, express then a few local stops until it reaches it's destination.

I'd have Basingstoke as the main interchange point between express services further West and the new semi fasts between there and London.

Currently the fastest service from Waterloo takes 42 minutes to get to Basingstoke.
aveeraging 70mph over 50 miles. We know the current max speed along here is in fact 100mph.

To double the average speed to 140 mph would probably need max speed to be nearer to 200mph.

Even a high speed line to Basingstoke that knocked 20 minutes off commute times would make a huge difference. Salisbury would become a commuter town of London for good or ill and a few of those little towns along the A30.

The fastest Southampton train would come down to an hour as well.

If you extended the high speed line to Southampton would only knock another 10 to 15 minutes off (but I expect the route really needs the extra capacity).

Half an hour knocked off Bournemouth trips would be worth something to those towns as well.

 

[Waverley125]

the obvious growth area is Bristol & South Wales, home to 3.2m people as a region.

OOC - Reading - Bristol - Cardiff - Swansea

obviously built with a Fishguard - Rosslare tunnel in mind, for services through to Cork and Dublin.

 

[ainsworth74]

the obvious growth area is Bristol & South Wales, home to 3.2m people as a region.

OOC - Reading - Bristol - Cardiff - Swansea

obviously built with a Fishguard - Rosslare tunnel in mind, for services through to Cork and Dublin.

Wouldn't it make more sense to serve Bristol seperate from Cardiff? Seems like a rather large double-back...

 

[MidlandMainlie]

Wouldn't it make more sense to serve Bristol seperate from Cardiff? Seems like a rather large double-back...

Depends on a new wether a new Severn Crossing is built e.g. Tidal barrage.

 

[ainsworth74]

Well at that point we really are moving into fantasy land I think. I'm not saying that the Severn Barrage would neccessarily be a bad idea but I can't see it ever happening.

 

[transmanche]

Wouldn't it make more sense to serve Bristol seperate from Cardiff? Seems like a rather large double-back...

London-Bristol-Cardiff is pretty much a straight line. So any doubling-back would be to shorten the HSx crossing of the Severn Estuary.

 

[TheGrew]

How deep is the Severn? Could you tunnel under it further downstream than the current crossing?

 

[YorkshireBear]

How deep is the Severn? Could you tunnel under it further downstream than the current crossing?

We can tunnel under the Channel so i imagine it is possible, whether it is wise is a different matter. The original Severn Tunnel was poor because they could not do the right ground investigations back then, so they hit a fault between rocks, the Chunnel did not do this and followed a full rock band all the way reducing significantly problems with water ingress. A new tunnel may actually be a good idea but very expensive. I think it may be a bit pie in the sky to get it to Cardiff i imagine it may just use the current Severn Tunnel.

On the barrage, while it is a sensible idea the environmental impact is simply too large i think for it to go ahead.

 

[transmanche]

How deep is the Severn? Could you tunnel under it further downstream than the current crossing?

The existing Severn Tunnel crosses the estuary at approximately the same location as the M4 Second Severn Crossing. So even if a second tunnel was constructed fairly close to the existing one (clear of any local faults) it wouldn't be too much of a detour.

Perhaps a new 4-track tunnel (2 for HS and 2 for conventional rail) might be better value in the long term, allowing abandonment of the existing tunnel.

 

[59CosG95]

A new tunnel à la Øresund/Fehmarn (immersed concrete) would be less expensive than a bored one, as multiple tunnels can be done in one sitting. The approaches would probably need boring though.

 

[bILLOO]

Long Buckby to London non-stop. Because, why not.

 

[anthony263]

The idea of a second Severn tunnel has been suggested especially with how old the existing tunnel is and all the work needed to keep it open

 

[Rhydgaled]

the obvious growth area is Bristol & South Wales, home to 3.2m people as a region.

OOC - Reading - Bristol - Cardiff - Swansea

obviously built with a Fishguard - Rosslare tunnel in mind, for services through to Cork and Dublin.

Probably said already earlier in the thread, but my idea for a westbound HSR would be in phases, as follows:

1. Old Oak Common to Heathrow
2. Heathrow to Reading West Junction (on the Reading-Westbury line, after passing to the south of Reading with a Reading East Junction allowing trains to serve Reading)
3. Reading West Junction to somewhere near Bath/Chippenham
4. Somewhere near Bath/Chippenham to Bristol Parkway / the Severn Tunnel
5. somewhere just west of Bath to Taunton

I haven't come up with anything to get into Bath/Bristol, so assume you'd just have to use the classic lines at those points. Another idea is to go from Heathrow to Southampton instead/as well as.

 

[joeykins82]

I think it's more likely that after Crossrail 2 comes online the excess capacity at Liverpool Street will be used to run a new HS line so Stanstead, Cambridge, Peterborough and on to HS2 at Toton. Delta junctions at Toton and somewhere in London enabling a connection to HS1 at Stratford International.

 

[HSTEd]

Why run the line from Liverpool Street?
King's Cross has superior positioning and can be more easily extended to take 400m platforms.

It would also concentrate high speed services on the Euston Road.

 

[edwin_m]

Why run the line from Liverpool Street?
King's Cross has superior positioning and can be more easily extended to take 400m platforms.

It would also concentrate high speed services on the Euston Road.

How? I make it about 300m from the stops to the tunnel mouth, so extending it for 400m trains would need a huge excavation plus a canal to deal with.

For what it's worth I don't think Liverpool Street would work either. The only place I can think of that would be vaguely suitable with reasonable onward transport would be a slice of the Olympic Park

 

[HSTEd]

How? I make it about 300m from the stops to the tunnel mouth, so extending it for 400m trains would need a huge excavation plus a canal to deal with.

Which can be dealt with by simply excavating the ground north of the tunnel mouth and putting the canal on a bridge over the approach.
We have seen more insane excavations for railway projects in the UK, just look at the amount of spoil excavated for Westminster's tube station.

You only need a hundred or so metres and if you demolish the PSB you should be able to avoid demolishing that art college.

 

[HowardGWR]

We can tunnel under the Channel so i imagine it is possible, whether it is wise is a different matter. The original Severn Tunnel was poor because they could not do the right ground investigations back then, so they hit a fault between rocks, the Chunnel did not do this and followed a full rock band all the way reducing significantly problems with water ingress. A new tunnel may actually be a good idea but very expensive. I think it may be a bit pie in the sky to get it to Cardiff i imagine it may just use the current Severn Tunnel.

On the barrage, while it is a sensible idea the environmental impact is simply too large i think for it to go ahead.

I just don't see the need. The Brunel and later Inglis route from Wootton Bassett is so good that very high speed can be laid out on it. The tracks are far apart (10ft) on the fast lines due to the BG until beyond Swindon.