Tram-train services between Sheffield and Rotherham, which have been plagued by problems, are running once again after a fault was detected on one of the vehicles.
Operator Supertram said an issue was identified on one of its Citylink vehicles on Tuesday night and further tests were needed to see if others in the fleet were affected.
The manufacturer detected a potential problem relating to the structure underneath the vehicle, known as the bogie.
Stagecoach said the issue related to a bracket on the bogie which was not linked to the mechanical running of the vehicle but added it had to be rectified before trams can go back into service.
Services were restored on Wednesday afternoon – with services running every 30 minutes between Sheffield Cathedral and Parkgate and a full service resumed on Thursday morning.
Supertram Managing Director Tim Bilby apologised for any disruption, adding: “We are pleased that the vehicle manufacturer has found a solution that allows us to resume the tram train service and we are sorry for the disruption this has caused our customers today.
“Safety will always be our first consideration and it was essential that this work was done.
“We are running a half hourly service between Parkgate and Cathedral for the remainder of today and will resume a full service tomorrow morning.
“Once again, I would like to thank our customers for their patience and understanding."
The scheme has been plagued by problems since it was first mooted.
It was due to launch in 2015 at a cost of around £15 million but it launched last year, with a bill of around £75m.
It was then involved in a crash on its first day of service at the junction of Staniforth Road and Woodbourn Road.
And in November, one of its vehicles was also in collision with a car at the same junction.