Train company Grand Central has begun operating a full timetable, ending months of setbacks following the firm's launch last year.
Grand Central was operating only one train
The East Coast Mainline link from Sunderland to London, via Teesside and North Yorkshire, began a limited service on 18 December.
Problems obtaining backup stock only allowed it to operate one train.
The firm began running three daily departures from both Sunderland and London King Cross on Saturday.
Managing Director Tom Clift said: "After lengthy delays while the overhaul work on our rolling stock fleet was completed, I am delighted that we have finally reached the position of being able to launch our full timetable."
The service stops at Hartlepool, Eaglescliffe, Northallerton, Thirsk and York.