On Thursday, President Obama signed a bill giving railroads an additional three years to install a more automated safety technology called positive train control on 60,000 miles of track. Congress passed the measure, which extended a Dec. 31 deadline, after industry executives and some lawmakers said the delays were the result, in part, of an “unproven and untested” safety system.

Image 2012 A head-on collision of freight trains killed two engineers and a conductor near Goodwell, Okla. Credit... Trudy Hart/The Guymon Daily Herald, via Associated Press

But internal corporate documents, independent studies and interviews with former Burlington Northern officials show that nearly 30 years ago, the industry had developed a technology that accomplished many of the functions of the modern train safety system.

Since 2004, about 77 deaths and more than 1,400 injuries could have been prevented if railroads had installed a system like positive train control, according to the National Transportation Safety Board. That includes an Amtrak train derailment that killed eight people and injured hundreds more in Philadelphia in May.

“No one is talking about putting a man on the moon or on Mars,” Senator Richard Blumenthal, Democrat of Connecticut, said in an interview. “We’re talking about a technology that was in place in the 1980s, and the failure to implement it is costing lives.”

The ARES system was rudimentary compared with the system the railroad industry is trying to install today, federal regulators say. Also, the older system was tested on only a few hundred miles of track with just a few trains, the regulators said, so it is not known how it would have worked in high-traffic areas like Chicago. Nevertheless, safety experts say the system proved that a technology to stop trains from colliding was feasible.