The incident was reported shortly before 1 p.m. at the 24th Street trolley stop.

Authorities said the trolley's driver saw 64-year-old Caltrans worker Stephen Palmer Sr. on the tracks and honked a horn to get Palmer's attention.

Palmer, who worked for the Caltrans Imperial Landscape Crew, saw the trolley but was not able to move away in time, according to authorities.

Commuter Jennifer Chavez rides the trolley everyday and said she was surprised the worker didn't see it before it got too close.

"It's a shame to hear somebody got hit because they weren't watching the trolley coming back and forth," she said.

The incident caused the closure of the trolley in both directions, authorities said.

Palmer was transported to UCSD Medical Center, where he was pronounced dead.

"We are still sifting through the details of what took place, and dealing with the shock of suddenly losing a member of our Caltrans Family," said Caltrans District Director Laurie Berman. "Our hearts are with Stephen's family and friends and the employees who worked with him. It is such a tragic loss."

Palmer worked for the Caltrans Imperial Landscape Crew based in San Diego. He had worked for Caltrans for the past four years and is survived by his wife and son.