Indonesia’s state power company PT Perusahaan Listrik Negara (PLN) estimates it will take a further three hours to restore electricity to Jakarta following a major power blackout in the capital and surrounding provinces, the company’s acting chief executive said Sunday.

“Hopefully for the Jakarta system, if everything goes to plan and the generating system is reliable, smooth supply should return in approximately three hours,” Sripeni Intan Cahyani told a news conference.

She said electricity customers in the provinces of West Java and Banten should get power back within four to five hours. “Hopefully it would not go beyond midnight,” she said.

PLN said disruption in an unspecified transmission system “resulted in the failed power transfer from east to west,” leading to electricity tripping out across all power plants on the central and western sides of Java.

The mass rapid transit system had to evacuate passengers from trains after the power outage, the company that operates the system said in a statement.

“The train stopped when we approached the station,” said Silviani, a passenger stranded at Sudirman Station in central Jakarta. “They said it was a blackout. So we got out and walked here.”

The outage caused traffic lights to go out in some areas of the capital as well as disrupting train networks and leaving some passengers stranded.