Governor Chris Christie blamed Amtrak for a holiday-weekend travel meltdown on New Jersey’s commuter train line, though the federal passenger railroad said it was the state’s fault this time.

As many as 1,200 New Jersey Transit passengers were stranded on April 14 in a tunnel beneath the Hudson River aboard a train that had lost power. A statement emailed by Christie’s office on Monday attributed the incident to Amtrak, which owns the tracks, calling it an example of the railroad’s “failure to adequately maintain its facilities.’’

The investigation so far, though, was “inconclusive’’ about a cause, according to Steve Santoro, New Jersey Transit’s executive director, who spoke to reporters in Hoboken on Monday. Santoro was there to show lawmakers damage caused by a fatal New Jersey Transit crash in September.

Mike Tolbert, an Amtrak spokesman, said its infrastructure wasn’t at fault and “the preliminary cause appears to be a NJ Transit mechanical problem involving the train’s pantograph,” or power collector.

The railroad in recent weeks sustained two derailments at its Pennsylvania Station in Manhattan, leading to days of service cancellations and delays on the Northeast Corridor, the busiest U.S. passenger rail route. Amtrak said it was to blame for both disruptions, one caused by a rotted timber support and another by tracks that failed to join correctly, the railroad said.

The latest incident left the train in the tunnel for three hours, disrupting New Jersey-bound service from Penn Station and jamming the station with travelers at the start of the Easter holiday weekend.