My view has been that a new inland bypass line is extremely unlikely, and a via Okehampton line is also highly unlikely, and the recent media evidence still suggests improving what already exists is all that NR are actively looking at.
It will probably be slower due to running underwater by then.
Speeding up the rail journey from Exeter eastwards while leaving such poor rail journey times west of Exeter is simply increaseing the perception that Plymouth and Cornwall are even further away from the rest of the country than they actually are. Its no wonder then that Tiverton Parkway has become a very popular rail head for business people and commuters from a wide swath of Devon and Cornwall now, served as it is west of Exeter by fast and direct daulled trunk roads from Cornwall A30, Plymouth A38, and now Torbay A380. ie Bodmin is just 60 minutes via the A30 from the M5 at Exeter compared to a 100 minutes by rail! So effectively what we have now in a 21st century south wset context is a fast main line direct to Exeter and the south Devon coast then a slow branch/secondary line on to Plymouth and Cornwall. Given Plymouths relative size and economic importance to the SW economy, ie HM Dockyard, one of the largest universities in the country and providing about 13K manufacturing jobs that situation is quite appalling really in 2018 especailly when you see what is happenning elsewhere.It will probably be slower due to running underwater by then.
Hopefully the next generation of trains will have some kind of submarine capability.
This scheme although not the best possible solution for any proper gains in travel times in the South West is probably the best that can be done at the moment with regards to the money available and keeping the route open that serves the current towns.
As has been pointed out by others the sea defences will need to be maintained anyway, and this effectively boots the problem a few decades down the line for the next generation to worry about.
If sea and water table levels continue to rise and that rise also starts to speed up, then much of the GWR route from the Somerset Levels right down to Newton Abbot will be under threat.
As will many of our coastal communities...
?Controversial argument: I think the A38 upgrade to motorway standard would deliver more benefits to the citizens of Plymouth and the S/W in general than a Dawlish avoiding line. That being said, why not both
Agreed. In terms of economic externalities, people in trains are much better than people in cars...thus we should encourage people to take public transit in general over private transit (I'm including taxis as a mode of private transit).
The point is that the existing line is the seawall protecting the towns. Even if the railway were to be removed somebody would still have to maintain the wall.
Note that driver Moses Clements, on City of Truro in 1904, was faster from Plymouth to Exeter than an HST nowadays.
Economists are taught that past investment is irrelevant when deciding policy (or something like that.) If you are in a hole, stop digging. So the recent sea wall expenditure isn't really relevant. However there is a clear public transport need along that bit of the coast, and there is also a need to improve the resilience of the west of England services, so I would say maintain the first and reopen the LSWR main line.
Given this morning's news of the urgent and critical need to accelerate decarbonisation of the whole economy, the answer has got to include massive modal shifts in transport. Public transport will have to be made better in every way including reconnecting lots of communities, electrification and battery-assisted trains in the gaps between the wires. Rebuilding and wiring the LSWR would be a good start. To control costs it could start as single line with dynamic loops, making sure that the track was in the right place for doubling when justified. The extra stock needed could be dual voltage EMU, with purpose-built compatible diesel locos for use in the gaps too long for battery power.
