A temporary timetable designed to alleviate rail delays caused by a landslip near Horsham was not "robust" enough and actually led to further delays and confusion on the platforms last night.
But Southern Railway says it has put in place a new timetable which should avoid further hold-ups while repair work is carried out over the coming weeks.
The landslip happened between Holmwood and Dorking during bad weather on Sunday night. Rain caused the ground under the tracks to fall away making the line unstable.
A spokesman for Network Rail said: "Around 15 meters of embankment has slipped meaning the track is not supported on one side.
"Because of the rural location, we have to build an access road to get machinery and equipment to the site which, combined with the repairs that need to be made, means the line could be closed for up to three weeks.
"We are doing all we can to get the work completed as quickly as possible and apologise for the disruption caused. Passengers should check with National Rail Enquiries or their train operator for the latest information."
It has caused severe disruption to the service between London Victoria and Horsham which calls through Warnham, Ockley, Holmwood, Dorking, Box Hill & Westhumble, Leatherhead, Ashtead, Epsom, Ewell East, Cheam, Sutton, Carshalton, Hackbridge, Mitcham Junction, Mitcham Eastfields, Balham and Clapham Junction all week.
Southern implemented a revised timetable yesterday but there were still severe delays to services in both directions.
A Southern spokesman said: "The temporary train service we put in place yesterday was as a result of the landslip but it wasn’t as robust as we had hoped. This is why we have now revised the service from today onwards."
There are now two services in each direction running between London Victoria and Horsham via Dorking in the morning and two more in each direction in the evening.
Journeys can be planned using Southern's website: www.southernrailway.com or National Rail Enquiries: www.nationalrail.co.uk.