A fire on board a Luas was caused by a worn-out hyrdraulic cable, rail investigators have found.
Passengers were on board the tram at the time of the incident in November last year.
The investigative report identified that a hydraulic cable was not fitted correctly to the tram. This caused it to rupture and release fluid which ignited.
The incident occurred on November 7 last year at 4.30pm, as the tram approached the Busaras stop on the Red Line in Dublin city centre.
The fire underneath the tram was first noticed by a tram driver travelling in the opposite direction, who notified the driver.
Officials at the Rail Accident Investigation Unit (RAIU) found that the cause was the hydraulic hose fretting, or rubbing, against a cable which caused it to rupture. Hydraulic fluid was released in a fine spray, which ignited and caused the flash fire.
Defects to these hoses were generally repaired within seven days of being discovered or during routine maintenance, it found. Checks after the incident found similar problems on 11 trams, and damaged components were replaced.
The RAIU report said that at "no point" did the fire penetrate into the passenger area of the vehicle. It found that specific instructions on how to install the hose to prevent fretting were not set out in maintenance manuals.