According to Caltrain, the power outage on the peninsula was due to “outside interference.”

SAN BRUNO, California. – Caltrain's train fleet was halted Monday afternoon due to a brief “power outage,” the transit agency said.

Trains were held up at the San Mateo and San Bruno stations.

“At approximately 2:15 a.m., Caltrain experienced a power outage at the San Mateo Station,” Caltrain spokesman Dan Lieberman said in a statement. “Caltrain employees and emergency responders determined the accident area was safe to travel and restored power to resume train service.”

Train service will resume at 3.10 p.m.

The outage occurred just days after Caltrain began operating its electric trains, but Lieberman said the outage was not due to the agency's infrastructure.

“It was determined that the power outage was not due to faults in Caltrain's infrastructure or the new electric trains, but rather to outside interference,” he said.

On Saturday, the agency celebrated the commissioning of 15 zero-emission trains equipped with digital display boards, surveillance cameras and power sockets.

In Santa Clara on Monday, some passengers on Caltrain 138 were visibly upset when the conductor asked them to leave the train and board the next one. One passenger told KTVU they no longer had a conductor to drive the train because of a shift change.

Some passengers report that their scheduled train was delayed even before the disruption or simply did not arrive at all.

“I have the app and checked it, but it didn't send any notification, so no one knew. There were a lot of people there who regularly take the train to work,” said Sahej Saidhu of Morgan Hill.

“Please fix this. We can't offer this on a regular basis. I expected better service because new trains are coming,” said Kevin Capati of Menlo Park.

For some passengers, the delays meant a tough start to the week.

“I live over in Half Moon Bay. So I take the train from Millbrae, come down here and then go back up. I waited for the 450 and it's not coming. So now I have to call Uber and spend $54 to get back up.”

Caltrain says it is not publicly discussing the cause of the outage, but wants to remind people that tampering with wires is dangerous and that interfering with railroad tracks is a crime.

They also say that power has been fully restored and that they expect service to return to normal on Tuesday.