More storms caused by global warming could lead to a loss of the South West's main rail link at Dawlish, according to a maritime forum chief.
Weather caused problems on the line twice in three years
Prof Laurence Mee says those who rely on the line, which runs along a sea wall, need to think of its replacement.
Network Rail said it had no plans to move the line at the moment.
It added that the Dawlish area was part of a 12-month pilot study into global warming effects and that it spent about £400,000 a year maintaining the track.
In two out the past three Octobers, bad storm surges caused serious damage to the line, which eventually finishes in Penzance.
Prof Mee, of the Devon Maritime Forum, and also director of the University of Plymouth's Marine Institute, said the line suffered from two problems.
He said: "One is that it gets overtopped [with seawater running over it] when we get winter storms, which is quite often.
"But the more worrying concern is if it is catastrophically washed away, which would really cut off a major part of the South West and affect the South West economy.
Met Office forecasters suggest this problem will not go away.
Bob Owens of Met Office said: "If you add together higher seas with storm surges, naturally there would be a tendency towards more damage along exposed coasts during the next 20 to 50 years."
Network Rail said it took the issue seriously which was why it spent so much maintaining the track.