In a photo provided by William Sun, people examine the wreckage of a New Jersey Transit commuter train that crashed into the train station during the morning rush hour in Hoboken,, N.J., Thursday, Sept. 29, 2016. The crash killed one person and injured 108. (William Sun via AP) (William Sun/AP)

The two governors — Chris Christie of New Jersey and Andrew Cuomo of New York — stepped up the microphone Thursday to say they didn’t know whether any sort of mechanical device could have stopped a commuter train from plowing into the Hoboken railroad station Thursday.

The people who run and regulate railroads know differently.

If New Jersey Transit had installed something called Positive Train Control — an expensive but vital device — the train would have slowed automatically to a safe speed before it entered the station, transportation officials said.

According to the latest Federal Railroad Administration accounting, New Jersey Transit hasn’t installed the system in any of its 440 engines or put in place 124 rail-side towers that would communicate with the trains.

PTC, as it’s commonly called, is an automatic braking system that saves lives. When eight Amtrak passengers died and 159 were injured in a Philadelphia train wreck in 2015, the National Transportation Safety Board concluded that PTC would have kept the train on track. The NTSB has advocated for installation of a PTC-type system for 45 years.

PTC became a hot issue on Capitol Hill in 2008. That’s when a PTC preventable collision in Chatsworth, Calif., killed 25 people and injured more than 100.

Congress reacted by passing a law mandating that railroads install PTC by the end of 2015.

The FRA followed through last year, threatening to fine passenger and freight railroads as that Dec. 31 deadline for PTC installation approached. But the railroads said they had had too little time to install the complicated system, and Congress listened to their plea, extending the deadline until 2018.

Congress, whose members have received more than $24 million in campaign contributions from the railroad industry since 2008, also said railroads could ask for up to two additional years after the 2018 deadline to complete the job.

FRA administrator Sarah Feinberg responded to that deadline extension by making clear that she expected regular progress reports from railroads, some of which have PTC systems nearly complete, while many others are well behind.

New Jersey Transit has not filed the required progress reports this year, according to the FRA website.

Fearful that some railroads may think the wiggle room granted by Congress gives then until 2020 to finish installation, Feinberg warned that unless railroads meet FRA benchmarks, no extensions will be granted beyond 2018.

Aware of FRA criticism, the Association of American Railroads, a trade group for the freight lines, said in May that it’s members have invested $6.5 billion dollars on PTC. They said the cost will climb to $10.6 billion to cover the 60,000 route miles of freight rail track.

AAR spokesman Ed Greenberg said the freight railroads plan to get the job done.

“The AAR has not been pursuing any further PTC extension,” Greenberg said Thursday. “The freight rail industry remains on schedule at having PTC fully implemented across the country and in accordance with the extension passed by Congress last year.”

Amtrak was able to meet the original deadline, turning on PTC in its Northeast Corridor in December. Though Amtrak owns most of the rail on which its trains run in the corridor, the balance of it’s operations are on track owned by freight railroads. To complete the PTC system, those freight railroads must install a system of way points with which equipment on board the train maintains contact.

The 2015 wreck in Philadelphia left rail cars strewn like toppled bowling pins beside the Frankford Junction tracks. One ripped open in a contortion of aluminum that left little looking like a rail car. Others, whipped off the tracks at 103 miles per hour, landed on their sides. Passengers hit the ceiling, flew out of broken windows, landed atop one another, were struck by flying luggage or were crushed in the twisted wreckage.

In addition to the eight dead, 46 people were seriously injured and 113 others suffered lesser injuries.