A person was struck and killed by a Caltrain on the southbound tracks Tuesday evening in Redwood City, according to the San Mateo County Transit District.

At 5:02 p.m., a southbound train struck a person trespassing at the Whipple Avenue grade crossing, the agency said. It was the sixth fatality on Caltrain tracks this year.

After the incident, trains were being single-tracked through the area. The tracks reopened in both directions at full speed about 6:30 p.m., transit officials said.

Despite the return to full service, passengers experienced delays throughout the system until late Tuesday night, the transit district said.