The small fire on the tram’s roof forced services to be suspended for several hours on Thursday as the private operator assessed the risk to its fleet.

There are calls for an investigation after the third fire on a Sydney tram in a week caused headaches for the morning commute.

Fire crews were called to Central station just after 8am on Thursday following reports smoke and flames were coming out from the tram’s roof at Surry Hills light rail stop, on the L2 and L3 lines. The ...