The crash of a Metrolink passenger train in California seven years ago that killed 25 people was caused by a devastating human error — the engineer missed a stop signal while texting on his cellphone — and Congress ordered a technological fix to ensure that such accidents never happen again.

The idea was to use global positioning satellites, sensors and sophisticated computers to track trains and prevent their crews from ignoring signals and speed limits. It was all supposed to be in place by the end of this year, but the railroad industry and government regulators will fail to meet the deadline by a wide margin.

The system is known as “positive train control.” Had it been operating on the northbound Amtrak line in Philadelphia this week, federal investigators say, it would have prevented the passenger train from accelerating to twice the posted speed limit and then derailing in a thunderous crash that left eight people dead and 200 injured.

“I can confidently say that an operational positive train control would have prevented this accident,” said Robert Sumwalt, a member of the National Transportation Safety Board, which is investigating the accident.

Across the U.S., fewer than 20 percent of the tracks scheduled for the new safety system have been equipped with it.

Safety experts, including former NTSB Chairman Jim Hall, say the railroad industry has dragged its feet and failed to make safety its top priority, though industry officials say they have been moving as swiftly as possible to phase in the new technology.

Edward Hamberger, president of the American Association of Railroads, said the delays have been caused chiefly by federal red tape, including a dispute between two federal agencies over jurisdiction for installing antennae. The technology that allows computers to intervene in the operation of thousands of trains all over the nation has also been challenging.

The delays are “not for lack of effort or lack of resources,” Hamberger said.

About half of the tracks in the Northeast corridor, the nation’s busiest, are equipped with the system on at least on one set of tracks, but it was not in place on the northbound curved section where the accident occurred.

Amtrak officials said Thursday they would have the system on its entire Northeast corridor by the end of the year.

The nation’s largest freight haulers are expected to complete installation of $9 billion worth of control systems across the country by 2020.

Two more years will be needed to test the system, placing the program about seven years behind schedule.

A bill moving through the Senate would grant the industry an extension from the original requirement to have the safety system operational by December.

Hall said it would be possible to proceed more quickly if the industry were willing to make additional up-front expenditures. “They are looking at safety as a formula rather than a moral obligation,” he said.