A railway tunnel should be built under a hill near Exeter to divert the main line away from a vulnerable coastline route, a Devon MP has said.
The line at Dawlish, which goes along the town's sea wall, can be hit by high waves.
Plymouth Moor View Labour MP Alison Seabeck said a tunnel under Haldon Hill would lower risks to the line from any climate change and speed up journeys.
Network Rail said the line in Dawlish was resilient to adverse weather.
Similar plans for a tunnel were first unveiled in the 1930s, but were abandoned after the outbreak of World War II.