OAKLAND, Calif. – The commuter train that struck and killed two San Francisco Bay Area transit workers didn’t have a front-facing video recorder, but interviews, inspections, audio recordings and camera footage from the train’s cab should provide enough evidence to determine a cause, a federal investigator said Sunday.

Jim Southworth, the National Transportation Safety Board’s railroad accident investigator-in-charge, confirmed that Saturday’s accident involved a Bay Area Rapid Transit train that wasn’t carrying any passengers because of the labor strike that has shut down the system since Friday.

But whether the work stoppage by members of the system’s two largest unions or the way BART management deployed nonstriking workers during the shutdown played a role in the fatalities will not be known for weeks or months, Southworth said.

“My concern coming out here, as it is for every investigation, is to find out what happened, to gather the facts,” he said. “Whether the strike plays a role in that I can’t say at this time.”

BART officials said Sunday that they could no longer discuss the accident because of the ongoing NTSB investigation.

BART’s assistant general manager has said that the four-car train with several employees aboard was returning from a routine maintenance trip and was being run in automatic mode under computer control when it struck the workers who were inspecting a section of track in the East Bay city of Walnut Creek.

Neither BART nor the county coroner has released the names and ages of the victims, one a BART employee and the other a contractor. They were the sixth and seventh workers to die on the job in the system’s 41-year history.

Southworth said it is too early to know how fast the train was going or if workers saw or heard it coming.