The Newquay to Par rail line will remain closed for another week to allow for emergency repairs.
The line had already been closed for two weeks for planned engineering work to lay new track as part of the Mid Cornwall Metro upgrade.
Network Rail is advising passengers that the closure will now continue until at least Friday, 6 December. This follows the discovery of a significant amount of displaced ballast - the stones that support and secure the tracks - near St Blazey. Engineers determined that repairs are necessary before the line can safely reopen.
The original closure, which began on 18 November, was to install new track into Newquay station and was scheduled to end on Sunday (1 December). However, the issue with the ballast is unrelated to this planned work, which remains on schedule.
Rail replacement services currently in operation will continue to follow the same timetable.
Simon Gillibrand, Network Rail’s head of metro railway operations, said: “We’re sorry for the disruption as a result of the emergency repair work taking place on the Newquay line.
“Safety is our top priority and we need to close the line while these repairs are carried out to ensure that everyone remains safe while travelling. We will do all we can to reopen the line as soon as possible.
“I’d like to thank passengers for their patience while we carry out these vital repairs.”