Authorities cite excessive speed as the possible cause of Tuesday's deadly Amtrak derailment in Philadelphia. But if the speed was an engineer's mistake, that error could have been corrected by computer technology, reports CBS News' David Begnaud.
In the Los Angeles area, where tens of thousands of people use commuter trains every day, Positive Train Control (PTC) is up and running and essentially lets a computer take over the controls of a train if it detects "engineer error" that could lead to potential danger.
"With a functioning positive train control system, as that train approached that curve, the technology would have actually slowed the train down or brought it to a stop in advance of it potentially speeding through the accident area," former Federal Railroad Association administrator Joseph Szabo said.
PTC uses GPS technology and ground sensors to determine whether to override the actions of a train engineer. R.T. McCarthy is director of operations for Metrolink in Southern California. He uses a simulator in Los Angeles to train his engineers on how to utilize PTC.
"It's telling me I have to break in 26 seconds. Now, in this case, I'm not going to break, I'm going to let PTC do its job," he said as he demonstrated the technology. "Now it's telling me in six seconds if I don't do anything PTC will take control. My speed is now 62 miles per hour."
Once the breaks kick in McCarthy said the operator can't stop it.
"It's done, whatever I can do, the system is now in command," he said.
Implementing PTC nationwide was a Congressional mandate in 2008 political action taken after a Metrolink train collided head on with another train in Los Angeles killing 25.
The driver of that Metrolink train was text messaging.
Had PTC existed, that would not have happened, says Metrolink public affairs director Jeff Lustgarten.
They've spent more than $200 million in the greater Los Angeles area and Lustgarten thinks it's worth it.
"Every penny," he said. "How can you put a price tag on people's lives?"
PTC technology doesn't just guard against human error. It can react quickly to bring a train to a halt, like in the event of an earthquake.
"We think it's the most important lifesaving technology you'll see on the rail system for years to come," Lustgarten said.
In the four months Metrolink has been using PTC, it's activated only once, and that was when a signal unexpectedly went red. In that case, the technology system stopped the train. It's estimated PTC could cost $10 billion to implement nationwide and that's one reason lawmakers are considering delaying that mandate until 2020.