Just two days before the 4th anniversary of the Chatsworth train wreck that killed 25 and injured 135 Metrolink commuters, the rail system rolled out new safety technology.
Called Positive Train Control, the system monitors trains by using global positioning. And if two get too close, a computer will warn the engineer and automatically apply the brakes.
The technology is a direct response to the Sept. 12, 2008, crash of a Metrolink train head-on into a Union Pacific train after leaving the Chatsworth station heading toward Simi Valley.
The Metrolink engineer failed to see a red stop signal because he was texting on his cellphone, investigators said.
Read more about Metrolink, the wreck and aftermath: