The services had been cancelled for the last three days between Mettupalayam and Coonoor due to landslip and a big boulder falling on the rack and pinion system track to carry out restoration works.
Since, works were still continuing, the service has been cancelled for December 18 also, officials said.
However, services between Coonoor and Udhagamandalam (Ooty) are being operated as usual, they said.