An outbound Metrolink train headed for Moorpark collided with a freight train on the Chatsworth side of Santa Susana Pass. Cars are off the tracks and rescues are underway. Triage teams are evaluating the injured. An MTA spokeswoman told Channel 4 there could have been as many as 350 passengers on board Metrolink train #111 on a Friday afternoon.

Updates from media reports:
* Two confirmed deaths, according to TV stations. The front Metrolink car and some freight cars have derailed. It's unclear whether the crash was head-on or whether the Metrolink train somehow overtook the freight. 5:08 pm
* Two rear Metrolink cars remain standing on the track, but with possible injuries. 5:11 pm
* Channel 4 anchor Ana Garcia just urgently ordered her aerial camera shot of the scene to be cut off, fearing that a dead body was about to be shown on live TV. The crash location is downstream from the first tunnel under Santa Susana Pass, east of Topanga Canyon Boulevard and Stoney Point in the stretch south of the 118 Freeway where the northbound tracks are just turning west in a residential area. The injured are being laid out on the grass of the private school adjacent to the tracks, but I'm sorry, I don't recall the name of the school. 5:16 pm
* Ventura train #111 left Union Station at 3:35 pm, Channel 2 says. 5:20 pm
* Live rescues are still being conducted in the two-level Metrolink car that lies on its side, more than 50 minutes after the accident. The LAPD has gone on tactical alert and hospitals in the city have gone on trauma alert. 5:24 pm
* A third fatality has been confirmed, Channel 2 reports. 5:26 pm
* The freight train belongs to Union Pacific and would typically have two crew members in the front locomotive, a spokeswoman told Channel 2. The rear cars of the freight train remain in the tunnel, she said. This is the sole track connecting Los Angeles with Ventura County, Santa Barbara and the coast beyond, so expect extensive disruptions in Metrolink and Amtrak service in California for at least the rest of today. 5:33 pm
* An hour since the accident, the triage mats — all colors — seem to be in greater use as firefighters work extensively inside the overturned first Metrolink car. A request has gone out for the LAFD urban search and rescue team, based on a belief that some victims are trapped under the car. 5:39 pm
* Former Times photographer Mike Meadows calls in a report from the scene to Channel 4. Anchor Paul Moyer introduced Meadows as an "amateur photographer," prompting Meadows to object that "I've worked in the business for thirty years." Meadows says he knows of at least seven fatalities. 5:46 pm
* Channel 4's Conan Nolan just spoke to a passenger with a broken leg who has yet to be transported, a strong suggestion that crews are still consumed with more serious injuries. 5:53 pm
* "How could it even happen, two trains on the same track?" witness Tom Lewis just asked on Channel 2. He said injured and dazed victims were "everywhere" as he helped remove victims from the cars. The engine that was pulling the Metrolink car appears to be fully surrounded by the overturned Metrolink car. 6:03 pm
* Channel 2's copter pilot says he can now see at least six covered bodies laid out next to the trains. 6:05 pm

Stepping away from the computer for an hour....KR