Metrolink has seen two multi-fatality crashes in the last decade and has focused considerable attention on improving safety and public confidence. Here is a review from The Times' archives:
What were the earlier crashes?
In 2005, a Glendale crash killed 11 people when a train hit a truck parked on the tracks. Prosecutors later said Juan Manuel Alvarez had intended to kill commuters as part of a sick attempt to gain attention from his estranged wife when he parked his sport-utility vehicle on the train tracks. He was sentenced to 11 consecutive life prison terms.
In 2008, 25 people died and 135 were injured in a crash in which a Metrolink commuter train collided with a Union Pacific freight train on a stretch of shared track in Chatsworth. Investigators say the Metrolink engineer went through a signal light that should have warned him to stop until the freight had moved.
Has Metrolink made safety improvements?
In 2010, Metrolink purchased Rotem cars that have energy-absorbing crush zones designed to redistribute the force of a crash away from passengers.
In Tuesday's crash, three of the four cars that derailed were equipped with that "crash energy management" system, a Metrolink official said.
The fourth car, a bicycle car, was not equipped with system.
In 2014, Metrolink became the first commuter service in the nation to roll out a sophisticated collision avoidance system designed to overcome human error. Had the so-called positive train control been in place, experts say, it would have prevented Metrolink's deadly Chatsworth crash. The tragedy prompted Congress to demand that the nation's freight and passenger railroads be equipped with positive train control by the end of 2015.
The technology relies on global positioning satellites, digital radio communications and computers to track trains. With computer-assisted dispatching and monitoring capabilities, the system can detect when trains violate speed restrictions, miss signals or enter the wrong track. In an emergency, it can override the engineer and apply the brakes.
There has also been debate about the practice of "pushing" trains from the rear with locomotives, a widespread practice that some experts fear leads to more severe accidents. It wasn't immediately clear whether the cars in Tuesday's accident were being "pushed" or "pulled."
There has also been an effort to improve the safety of train crossings.
What about ridership?
Annual ridership has dropped by almost 595,000 passengers since 2008. Officials have blamed the recession.
FROM THE ARCHIVES: