-- The New Jersey train crash that left one woman dead and 114 others injured has re-ignited a debate over an automatic train-braking system called positive train control.
Positive train control (PTC) deploys automatically when trains run above the speed limit, among other scenarios.
According to New Jersey Transit’s last quarterly filing, dated July 2016, none of the company’s 400+ locomotives were equipped with PTC software, nor was its track. According to that same report, filed with the Federal Railroad Administration, the company had installed some hardware components on eight trains, and scheduled a pilot demonstration for a 6-mile segment of track. NJT does not dispute the report.
Investigators can’t yet say what caused today’s deadly crash, so it's unclear as to whether PTC could have prevented it, as some have suggested. NJT has declined to answer questions from ABC News.
According to the FRA, PTC is "communication-based/processor-based train control technology" designed to prevent train-to-train collisions, derailments caused by speeding, and incursions into established work zones among other functions.
The National Transportation Safety Board confirms its experts are looking into the role PTC might have played, had it been installed -– and New Jersey Gov. Chris Christie said the train appeared to be traveling at a “high rate of speed," despite the 10 mph speed restriction coming into the station.
However, in the past, those experts have asserted that PTC could have prevented fatal accidents, like Amtrak 188, which hurtled off the tracks, killing eight, in Philadelphia last May. That train was traveling 106 mph into a curve that was restricted to 50 mph.
If the feds had had their way, they say the Amtrak crash could have been prevented: PTC was originally supposed to be implemented nationwide by the end of last year.
Following a spate of fatal crashes in the early 2000s -– most notably a September 2008 collision between a California Metrolink Train and a Union Pacific freighter that killed 25 people –- Congress passed the Rail Safety Improvement Act in 2008.
The legislation allowed the FRA to set a deadline: all railroads that regularly transported passengers or hazardous materials were ordered to install PTC by Dec. 31, 2015.
But the railroads fired back, with trade organizations decrying the deadline as “arbitrary" and "unworkable.”
After months of wrangling -– and over some lawmakers’ vigorous objections -– Congress voted in late 2015 to extend the deadline by three years, to Dec. 31, 2018, giving some companies the option to extend the deadline an additional two years if they met certain conditions.
“This five year extension of life-saving technology is way too long, with way too little guarantee that PTC implementation will get done,” Sen. Richard Blumenthal, D- Conn., said at the time.
The railroads, however, rejoiced, with multiple companies pledging to spend hundreds of millions on implementation.
The FRA required the railroads to submit a PTC plan by January 2016 outlining “when and how the railroad would have a system fully installed and activated.”
Though the NTSB urged railroads not to apply for extensions, the FRA approved several extension requests, including some from commuter lines, like the Massachusetts Bay Transit Authority, as well as some larger freight companies, like CSX and Norfolk Southern.
According to the FRA, New Jersey Transit’s target implementation date is in 2018. Amtrak, the company involved in the deadly May 2015 derailment, has activated PTC on most of its track in the Northeast corridor.
Meanwhile, the NTSB continues to urge railroads nationwide to hurry up and implement PTC.
“The NTSB has been recommending positive train control for 40 years,” Member Bella Dinh-Zarr reminded reporters in Hoboken today. "We will look at whether there was positive train control installed, and all of the aspects related to that before we come to any conclusions."
ABC News' Jeffrey Cook contributed to this report.