Federally mandated safety technology that experts said may have prevented Thursday’s deadly NJ Transit train crash in Hoboken remains years away from being implemented on most railroads, including the LIRR.

Positive train control technology, or PTC, aims to remove the possibility of human error in several potentially deadly situations.

Radio transponders installed on tracks and on trains communicate with each other to automatically slow down or stop a train if it’s going too fast, is about to hit another train, or violates a signal.

The U.S. Safety Improvement Act of 2008, drafted after a Los Angeles collision between a commuter train and a freight train killed 25 people, required all railroads to have PTC in place by December 2015. But with most railroads making relatively little progress by late last year, the federal government agreed to push the deadline to 2018.

Metropolitan Transportation Authority spokesman Aaron Donovan said Thursday that the Long Island Rail Road and Metro-North “remain on target to implement PTC by the 2018 deadline” at a cost of about $1 billion.

But in its last progress report to the MTA board in June, the railroads identified several “major project issues,” including delays in design, manufacturing and delivery of equipment.

While declining to speculate on whether PTC could have prevented Thursday’s crash, National Transportation Safety Board Vice Chairwoman Bella Dinh-Zarr said the agency has been calling for the technology for four decades.

“We know that it can prevent accidents,” she said.

Moriches railroad safety consultant Carl Berkowitz criticized the railroad industry for its “lax” approach to positive train control, which he believes could have prevented Thursday’s crash by automatically applying the train’s emergency brakes as it sped toward the station, as witnesses have described.

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“Would that have made a difference? I think it would,” Berkowitz said. “I always look back and say, ‘This PTC was supposed to be installed years ago.’ ”