Preliminary investigations have revealed that the blackout, noise and smoke in a carriage on Line 2 was caused by a short circuit between the train and pantograph, the operator of Shanghai’s metro line said on Wednesday afternoon.

Passengers alerted the police at around 11 am on Wednesday after hearing noises coming from the Line 2 train that was traveling between Shanghai Science and Technology Museum Station and Century Avenue Station. Smoke was seen shortly after.

The publicity department of Shanghai Shentong Metro Group has denied claims from social media users that the smoke was caused by an explosion.

The department also said in a news release that the train driver took the necessary emergency measures by stopping the train at the station and helping evacuate passengers. No one was hurt during the incident.

The metro service resumed after the train was pulled out of operation.
Authorities were still investigating the incident.