Storms smashed a hole in the sea wall alongside the line above the seafront in Dawlish, south Devon in 2014.
The railway line took two months to repair at an estimated cost of £1bn to the local economy.
Network Rail is consulting with Devon and Cornwall residents about the plans.
They include strengthening defences and cliffs, as well and building breakwaters to protect the line.
More on the coastal rail protection work, and other Devon and Cornwall news
Cliffs next to the line would be stabilised and reshaped so they are not as steep under the plans.
A total of £270m is allocated for spending on priority areas including around Dawlish between 2019 and 2024.
The line connects Devon and Cornwall with the rest of the UK.
Protecting a key coastal railway track from rising sea levels and falling cliffs is going to cost about £650m, Network Rail has said.