Trains between Buxton and Hazel Grove were suspended while engineers worked to remove 15ft-long icicles which had formed in a railway tunnel.
Network Rail said no trains were able to run through the area in either direction until the giant icicles in Eaves Tunnel, near Chapel-en-le-Frith, have been cleared.
The icicles "pose a safety risk for drivers and passengers should they hit, or be hit by, trains".
A Network Rail spokesperson said: “Due to the treacherous conditions at Eaves Tunnel, we’ve closed the Hazel Grove to Buxton line to trains for safety reasons.
“To get the line up and running as quickly as possible, we’re using a number of methods. This includes using our own snow ploughs, road rail vehicles, as well as installing scaffolding inside the tunnel to hack away at the sheer number of icicles that have formed as a result of the cold weather.”
The line has been blocked in either direction since Sunday due to the problems with the ice and drifting snow.
National Rail said the route was expected to remain closed for the rest of today (Monday).