The danger is that far too much money will be spent on the coastal route and that vastly better resilience than it has now will never be achieved. With worsening conditions, it is possible that no real progress will be made and all the while there will have been no attempt to create route diversity, once a great strength of the British railway system.
Short of tunnelling behind the cliffs, no amount of work will make this route invulnerable: it only needs to fail in one place to stop trains. As was said after the Dawlish débâcle in 2014: "The challenge is to ensure that the existing line has the greatest possible resilience, but to have readily available an inland diversionary route between Exeter and Newton Abbot."
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