The incident occurred shortly before 6 p.m. Thursday on Madison Avenue just south of Indiana Avenue. Investigators say the crossing arms were down.
Riverside police say Angel Gonzalez waited for an eastbound train to pass before he crossed the tracks, what he didn't notice was a westbound train passing at the same time. He was hit by that train and killed instantly.
"I guess he didn't see the other train pass by and he just got hit," said friend James Shoakzode.
Gonzalez's godmother, Rosalinda Rojas, says he was out in the neighborhood riding his bike.
"He just was suppose to go around the block and come back home. He never made it back home," Rojas said.
This is not the first time the teen's high school has been shocked by a tragic event. For a second time this year, Arlington High School is in mourning.
In August, Tyler Lewellen died after he collapsed on a football field. Rojas says the two boys were friends and that the family helped raise money for Lewellen's funeral. Now, they need the help.
"We need all the help we can get. We have nothing," said Rojas.
Gonzalez's death comes just a month after the high school held a railroad safety assembly where students were taught to stop, look and listen.
It's a program that was emphasized following the 2009 death of another Arlington student, Samuel Sung Jae Shin, who died the exact same way as Gonzalez at another railroad crossing. The city says it is trying to make rail crossing safer.
"There are a lot of underpasses now that have been either built -- and a couple of overpasses -- to separate vehicles, pedestrians, bikers from the potential of an accident like this," said Riverside Mayor William "Rusty" Bailey.
Family and friends of Angel Gonzalez's family and friends are planning to hold a candlelight vigil Friday night in his memory.
"He was a really good guy," said Shoakzode. "He was always funny. He will always be that person who'll make your day."
For anyone who wants to donate to the funeral cost, the Serafin "Angel" Gonzalez Memorial Fund has been set up at Visterra Credit Union.