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
A spokesperson for Network Rail later confirmed the discovery of the sink hole and the line closure.
“We’re sorry to passengers disrupted this evening while our engineers are investigating what caused a sunken area of track foundation stone at Broughton Ferry,” said the spokesperson.
“For safety reasons the railway will stay closed while find out what caused the ballast stone to dip.
“We’re working as fast as we can to get the railway reopened and we thank people for their patience.
“We’d advise anyone travelling tonight to check National Rail Enquiries or with their train operator for the latest travel information.”