The Sheffield to Rotherham tram-train service, which has been plagued by problems since it was first proposed, has been suspended this morning.
Stagecoach Supertram, who are operating the £75 million pilot project, said services were suspended due to a points failure.
The company advised passengers to find alternative options and said tram-train tickets were being accepted on the X1 service between Rotherham and Sheffield.
The tram-train project launched in October – almost three years later than originally planned and at five times its original cost.
One of the vehicles was involved in a crash with a lorry carrying gas cannisters on its launch day.
Four people were injured in the incident, with one taken to hospital.
The crash happened at the junction of Woodbourn Road and Staniforth Road in Darnall.
One person was also injured following a crash between a tram-train and a car at the same junction in November.
The pilot project has cost around £75 million – £60 million more than original estimates – and was originally due to launch in 2015.