Network Rail and engineers have begun work to repair a landslip between Edenbridge and Godstone on the Redhill-Tonbridge railway.
The railway has been cut in half since 22 December, when a train driver noticed the track starting to dip on a 12m high embankment.
It follows a month of rain in one week.
The slip is one of the largest the railway of the South East has faced in many years.
The line is expected to reopen by the end of March