Train services through Dundee and Angus have resumed after a sinkhole was discovered on the line near Broughty Ferry.
ScotRail confirmed on Thursday morning the safety inspection of the track has now concluded with services now operating as normal.
The east coast main line was closed in both directions on Wednesday afternoon and evening.
The northbound side reopened in the afternoon, meaning services could return to Aberdeen.
However the line towards Dundee had remained closed whilst engineers investigated the extent of the damage.
ScotRail advised passengers on Thursday that 09.36am service from Broughty Ferry to Edinburgh would be going ahead as scheduled following the safety inspection.
CLEARED: Disruption caused by a safety inspection of the track at Broughty Ferry has now ended. ^Chris
— ScotRail (@ScotRail) July 29, 2021
Wednesday’s disruption had seen some replacement bus services put on to take passengers between Dundee and Montrose.
A statement from Network Rail said: “We need to perform a safety inspection of the track in the Broughty Ferry area.
“For safety reasons train services will be unable to run through this area.
“Please check with your train company for travel information.”
LNER – which runs services between Aberdeen and London – initially said the problem had been caused by an “obstruction” on the line.
But in response to one customer it has now been confirmed a sinkhole had been discovered.
Because there is a sink hole that has since been discovered so it is unsafe to run a service through the area. Rail replacement coaches are being soured for you to continue your journey. ^CMc
— London North Eastern Railway (@LNER) July 28, 2021
Network Rail later confirmed the discovery of the sink hole. They said a 20mph limits is in place on the southbound line, to allow the newly repaired track bed to settle.
A spokesperson said: “Our engineers worked through the night to repair and reopen the line as quickly as possible for passengers.
“We apologise for the inconvenience this incident caused to customers on Tuesday evening.”
