San Mateo County (Map, News) - A Caltrain fatally struck a 15-year-old boy wearing headphones as he rode a skateboard around a lowered crossing gate at the San Bruno station Saturday, marking the fifth death on the tracks this year, authorities said.

Anthony Rea, of San Bruno, rode through a pedestrian crossing on the north end of the San Bruno Caltrain station around 5:30 p.m. when Caltrain No. 440 slowed down to enter the station on its southbound trip to San Jose before fatally striking the boy, Caltrain spokeswoman Christine Dunn said. Wearing his headphones, he had gone around the gate on his skateboard prior to the train’s arrival, she said.

Dunn said it was unknown what speed the train was traveling when it hit Rea but that it did not have to be moving fast to kill him because of the train’s size.

“The gates are there for a reason and it’s really important for people to be aware of that,” she said.

There were just four trains in operation during the time of the incident. Trains were delayed until both tracks were reopened at 8 p.m., Dunn said.

Rea was the fifth fatality on the tracks to date this year. There were eight deaths last year after a record 17 people were killed in 2006. Three of the previous four deaths this year were ruled suicides while a recent death in a San Francisco tunnel is still under investigation, Dunn said.

Dunn said she had just given safety-awareness lectures to three classes at San Mateo High school on Friday. The classes are designed to raise awareness and caution teens around the tracks, Dunn said.

“We start them young in terms of working with the schools to have train-safety classes and trying to teach them respect for the train and it doesn’t seem to be working,” said Jerry Hill, a member on the Caltrain board of directors.

Teens dying on the tracks are nothing new. A Caltrain fatally struck Jose Luis Flores, 17, in Redwood City in January. Michael Bulnes Jr. was hit by a train at a railroad crossing in San Bruno in 2000. His family sued Caltrain and Amtrak but a San Mateo County jury ruled in 2005 that the transit agencies were not responsible for his death.

The family of Fatih Kuc, 13, sued multiple agencies including Caltrain after a train struck and killed him in Burlingame in April 2006. The Kucs’ attorney would not release details of a tentative settlement.

mrosenberg@examiner.com