Police used a stun gun to subdue a disruptive man in an overcrowded New York railway station, sparking a stampede after false rumours of gunshots.

The pandemonium came after a train with about 1,200 passengers became stuck in a tunnel between New York and New Jersey for nearly three hours.

It was the latest in a series of recent rail problems plaguing the metropolitan area.

The New Jersey Transit train became disabled in the Hudson River tunnel late yesterday afternoon, when Amtrak was experiencing overhead power problems.

A New Jersey Transit spokeswoman said the train finally reached New York's Penn Station in the early evening.

The overcrowded train station erupted in panic when Amtrak police used a Taser on a man who was causing a disturbance.

New York police said the use of the Taser led to false rumours of gunshots at the station, and people screamed and ran, leaving the station strewn with abandoned bags.

The nearby Macy's department store was briefly locked down. Sixteen people suffered non-life-threatening injuries, police said.

Amtrak said the subdued man, who was not a passenger from the stranded train, was in police custody.

The loss of power in the tunnel caused delays of an hour or more on Amtrak and New Jersey Transit.

It happened three weeks after the derailment of an Amtrak train at Penn Station and a week after a New Jersey Transit derailment shut down eight of 21 tracks there and disrupted travel in the region for days.

One passenger from Friday's train, Mia Sanati, described a scene of confusion.

She said she and her husband were heading for the New York International Auto Show when they boarded the train in Secaucus, New Jersey.

Shortly after the train entered the tunnel to go under the Hudson River, they felt a bump on the side of the train and saw sparks.

"About 30 seconds later, the train just came to a complete stop," Mrs Sanati said.

The power went out, except for emergency lights, and so did the air conditioning, she said.

"It got really hot really fast, with that many people crammed together."

New Jersey Transit executive director Steven Santoro told affected passengers: "We deeply apologise for your experience, and I would like to hear from you."

NJ Transit spokeswoman Nancy Snyder said the railroad was working with Amtrak to discover the cause of the problem.