The accident happened on the eastbound 210, just west of Irwindale Avenue at about 9:30 p.m. Saturday.
Witnesses said the SUV was in the slow lane and was merging onto the freeway when it hit a fence and ended up on Metrolink tracks just outside the Miller Brewing Plant.
Two children were ejected from the vehicle and taken by helicopter to Children's Hospital Los Angeles.
Their conditions were not immediately known. Other victims were transported to County USC Medical Center.
The cause of the crash was under investigation.
City News Service contributed to this report.