Authorities say the fiery collision occurred shortly after 5:30 a.m. near the intersection of Rosecrans and Marquardt avenues. Fire crews believe the RV stalled at the Rosecrans Avenue intersection and was struck by the OC Line 681, which was carrying over 100 passengers and was heading from Orange County to Los Angeles.
Dramatic video shared on social media shows the moment the train slammed into the RV and pushed it along the track. The video appears to show people fleeing from the RV, and witnesses told police four people were seen running from the site of the collision moments before the crash.
Firefighters were seen dousing flames that gutted the vehicle and charred a rail car. Smoke from the fire could be seen for several miles.
Flames engulf Metrolink train after crash on tracks in Santa Fe Springs
"We got buffeted around pretty good, and it felt like we might derail for a second or two," train passenger Mike Lozano said.
Shortly after the collision, a freight train arrived on the parallel tracks.
"You could hear it coming, and it was coming really fast, you could tell," Lozano said.
Another passenger said he braced for potential impact as he heard the sound of the freight train quickly approaching.
"That was honestly the longest few seconds of my life, like when I heard the train horn coming, I was just looking around, everyone was looking around, are we even going to be safe? Do they know that this just happened? Because it sounded like they didn't," Ryan Hajek described.
The freight train ran over debris from the crash before coming to a stop as the fire from the Metrolink train started to spread.
AIR7 HD was over the scene, where dozens of evacuated passengers waited in a nearby parking lot while crews battled the flames. Four passengers who suffered minor injuries were treated and later released, according to officials.
"The hit was such an impact on the train," passenger Rosalind Carter said. "I remember being flung into the seat next to me, I hit my head, it was just pretty traumatic."
WATCH: Passenger describes frightening experience following Metrolink crash
The crash caused significant train delays and cancellations. Metrolink offered ticket reimbursements for some customers and advised affected passengers to find their own transportation as "alternate" transportation was limited.
Many passengers who frequently ride the train said the crash could've been a lot worse but were thankful for the quick response of Metrolink employees and first responders.
"I got a couple more weeks of work, I'm retiring in December. So yeah, just wanna get through this thing and come out on the other end," Lozano said.
A search is underway for the occupants of the RV, who may face hit-and-run charges.