Network Rail has invested more than £8.5m over the last 10 years to protect the railway line along the Dawlish and Teignmouth coast line.
Climate change experts have warned that sea levels could rise making the line more difficult to protect.
An alternative line would cost about £100m and would pass through Okehampton, Tavistock and Plymouth. Anne Marie Morris conserative MP for Newton Abbot said "the cost of sea defences was money well spent and the existing line brings an awful lot of wealth to Dawlish and Teignmouth.