A man struck by a Boston-bound MBTA train and trapped under its wheel just north of Route 128 Extension in Gloucester late Sunday night died from his injuries shortly after he was freed by rescuers.

Identified by police as Jeffrey Tupper, 47, of 270 Main St., Gloucester, the man was hit just before 10:15 p.m. and was trapped for around an hour and a half beneath a 50-ton carriage.

After being transported by Gloucester Fire Department ambulance to Addison Gilbert Hospital, Tupper was pronounced dead shortly after midnight.

Rescuers from the Gloucester Fire Department used air bags to lift one end of the train car, estimated to weigh 50,000 pounds, 3 inches in the air so that Tupper could be removed.

A Med-Flight helicopter landed on Route 128 Extension to fly Tupper to a trauma center, but when he was freed, paramedics determined that his condition would not permit air travel and the decision was made to take him to Addison Gilbert, around a mile away.

The commuter train was traveling around 40 mph between Rockport and downtown Gloucester when the engineer spotted someone lying across the tracks as they make a bend to the left from Babson Reservoir and then pass underneath Route 128 Extension, the engineer of the locomotive told police.

The engineer said he immediately hit the brakes, but the train's momentum carried it into Tupper, who was lying with his mid-section over the outside rail, and pushed him around 100 feet before grinding to a stop.

Interim Gloucester police Chief Michael Lane said yesterday the department was approaching the incident as a tragic accident. A spokesman in the Essex County District Attorney's office said foul play is not suspected and the state medical examiner will determine both the cause and manner of death.

According to the police report, a bottle of vodka one-fifth full was found near the site of the collision along with two bottles of prescription psychiatric medications.

The problem of extricating Tupper from underneath the train without causing further injury resulted in an effort involving several agencies and local companies described as by police as "heroic."

The train was travelling from Rockport with the engine in the back pushing and the engineer driving from the front carriage at the time of the collision.

Rescuers determined that releasing the brakes to reverse the train risked it rolling fatally forward.

A crew specializing in the recovery of derailed locomotives was called in, but could not reach the scene from its base in Wellesley in less than an hour.

Tally's tow service was called and brought an oversized wrecker used for lifting tractor trailers, but was not able to maneuver to the train on the tracks.

With those options exhausted, firefighters turned to a new air bag used to lift heavy objects that was ordered along with the city's newest ladder truck, Deputy Chief Miles Schlichte said. The air bag was fetched from storage in Magnolia, unpacked from its box and given its first-ever test on the Route 128 Extension, before being lowered down an embankment to the tracks.

At the same time, police contacted managers of the Building Center on Harbor Loop who agreed to mill lumber to brace the train should it become unstable on the air bags.

From the Route 128 Extension, the air bag was lowered down the embankment to the accident scene and inflated high enough to release Tupper.

"It was a great coordinated effort by all agencies involved," said Police Lt. Tom Williams yesterday. "It was a heroic effort by police and fire and all involved."

When he was removed under from the train and brought up the embankment on an all-terrain vehicle, paramedics found Tupper's injuries worse than previously believed, essentially canceling the Med-Flight.

The 18 passengers on the train from Rockport were kept on board until Tupper was taken from the scene. They were transported by Cape Ann Transportation Authority bus to another MBTA train station.

An MBTA spokesman said that, aside from the commuter train involved in the incident, only one other train was delayed because of the crash.

All trains were running on schedule yesterday morning, he said.

Patrick Anderson can be reached at panderson@gloucesterimes.com