A broken railway line led to the cancellation of all trains between Nottingham and Newark Castle on Friday morning.
East Midlands Railway (EMR) said the damage was found on the line between Fiskerton and Bleasby.
The cancellations affected all services on the Matlock/Derby/Nottingham/Cleethorpes route and the Crewe/Derby/Nottingham/Lincoln route.
The rail operator said diverted services can expect an extended journey time of up to 60 minutes.
EMR says engineers have already investigated the rail and are carrying out emergency repair work, expected to be complete by 14:30 – but the advertised train timetable is not expected to return until 16:30.
Appropriate rail replacement buses are being put into pace for all affected passengers, with all available information and timings on the EMR website.
