A new inland mainline is one of the radical proposals being called for as part of industry demands for a "major rethink" of the Westcountry's fragile rail network.
Flooding in November and December effectively cut off the region for rail passengers, leaving tracks submerged outside Exeter and the coastal branch closed then severely delayed following a massive landslide at Teignmouth.
The Institution of Civil Engineers in the South West (ICE) is seeking an urgent review in the summer, amid concerns that the existing infrastructure is struggling.
It also wants consideration of a plan to roll out the new electrification project south of Bristol, via a new feasibility study.
Network Rail says it is working to strengthen the resilience of the region's lines, but has ruled out any major projects in the next five years, estimating that funding for a new line avoiding the coast would stretch into the hundreds of millions of pounds.
Trish Johnson, regional director of ICE South West, said the region was disproportionately affected by snow, freezing conditions and flooding.
She added: "There are only two routes into the far South West by road, Flybe is cutting jobs at Exeter airport, and Plymouth airport has been closed, therefore keeping rail networks open is vital.
"The stark reality is that, in times of severe weather conditions, areas of the South West are effectively cut off."
The ICE says that even in good weather, rail journey times across the South West are a source of constant frustration to travellers.
It welcomes plans to create a direct rail link from Reading to Heathrow and expects improvements to Reading station will have a positive impact on journeys to London.
But it argues that plans to bring the new High Speed Two (HS2) route to Bristol are "less promising" for the southern part of the greater South West region.
South West member of ICE Council Richard Fish said he wanted "serious action and investment" to address the very real rail issues".
"Signalling improvements and full dual-line capacity on the Exeter to Waterloo line would create a real main-line alternative to London," he added.
John Baker, Wales and West spokesman for Network Rail, said the problems "west of Bristol" were under discussion with MPs and stakeholders as part of plans to "strengthen resilience", but said: "We have no plans to electrify lines west of Bristol in the next five years.
"Moving the line inland is a long-term project, costing hundreds of millions of pounds, needing political will and years to complete a feasibility study."
