Commuters were evacuated from a busy train as it left Caerphilly railway station when the driver spotted smoke coming from underneath it.
The 7.24am service from Rhymney to Penarth had just left the railway station at around 8.25am this morning when smoke was seen coming from underneath the front unit, according to Arriva Trains Wales.
South Wales Fire and Rescue Service were called, but left at around 9.30am.
Arriva Trains Wales has confirmed there was no fire.
No smoke was in the cabin and no passengers were injured, a spokesman for the train company said.
Engineers have moved the train to the Canton depot and the line is now reopened, although disruption on all services between Cardiff and Rhymney are expected until at least midday.
#ATWUpdate Due to an operational incident at Caerphilly, the line is blocked. Train services running through this station may be cancelled or delayed.
?Ticket acceptance with Stagecoach route 26 Caerphilly to Ystrad Mynach
Disruption is expected until 12:15
— Arriva Trains Wales (@ArrivaTW) October 11, 2018