A 15-year-old Freedom High School sophomore and aspiring kick-boxer was hit and killed by a train Wednesday night in Oakley as he walked on the tracks, police said.

Aaron Griffin, 15, of Oakley died from extreme blunt force injuries, a Contra Costa County coroner's office official said.

The boy was walking eastbound on a railroad trestle near Vintage Parkway and Main Street around 4 p.m. in the same direction as the train, Oakley police Sgt. Jeff Billeci said.

The train operator told investigators he saw Griffin on the tracks slammed on his brakes and honked the horn, but could not stop in time.

Friends of Griffin said Thursday that he was wearing an iPod at the time of the accident and may not have heard the oncoming train.

Best friend and classmate Javier Green, 15, of Oakley said Griffin was almost home from a friend's house at the time of the accident. He said Griffin would often jump a fence to take a shortcut home.

The aspiring mixed martial arts fighter had spent Wednesday at the friend's house, where he often sparred, Green said. Griffin was taking five kick-boxing classes to learn the sport.

Green received the bad news from one of Griffin's three brothers Wednesday night.

"I was, like, crying, and I felt really bad," he said.

Word spread quickly to other friends.

"It was a shock to find out. Most of us just saw him, and now we found out he's dead. Everybody is just pulling together," said friend and classmate Leikin Poppino, 16, of Oakley.

She remembered seeing Griffin for the last time Monday.

"We had a little wrestling match, and he totally pinned me," she said.

"He was always kick-back, always smiling and always laughing," she said. "He was a really great guy."

Photos and remarks posted on friends' MySpace pages showed Griffin playing drums and skateboarding. Griffin had started fan sites for the TV show "Family Guy" and the band System of a Down.

Four Burlington Northern Santa Fe engines were moving between sites at the time of the accident, near Oakley City Hall, company spokeswoman Lena Kent said. One of the engines struck the boy, she said, adding that the company's railroad police are investigating the case.

People often walk on the section of railroad tracks where Griffin was hit, Billeci said.

"Kids do cut through there all the time, and homeless also walk through there," he said.

Billeci estimated one pedestrian a year gets hit by passing trains along Oakley's tracks. The railroad tracks throughout Oakley have numerous pedestrian access points.

Although city and railroad officials have not discussed pedestrian overcrossings for the railroad, several agencies have joined together to construct an undercrossing for vehicles that could enhance public safety and improve access at Main Street and Rose Avenue.

Freedom High principal Eric Volta notified all of the teachers on campus about Griffin's death, said Steve Amaro, the school's athletic director.

There will be a moment of silence in Griffin's honor at today's junior varsity tennis tournament, Amaro said.

"Whenever you talk about students who die early, it is hard," Amaro said. "Freedom has been fortunate in the last few years with no student deaths, but there is always the potential for it."

Freedom High has been closed this week for spring break.