A study commissioned by the state Department of Transportation recommends Metro-North Railroad ease commuter crowding by introducing double-decker coaches on the New Haven Line.

The bilevel cars can carry about 146 passengers, while single-level ones hold about 110 people, Metro-North spokesman Dan Brucker said.

Bilevel trains, popular in Europe and also are used on commuter rail lines in places such as Chicago; Long Island, N.Y.; Boston; and Canada.

“Customers find them very appealing,” Brucker said. “They like the appearance and ambiance and find it very attractive.”

A major obstacle to the plan is the 50-block-long Park Avenue Tunnel to Grand Central Terminal in New York City, Brucker said. The tunnel is 16 feet tall, about the height of the double-deckers.

Surveyors are looking at whether there is adequate clearance in the tunnel for existing or custom-made bilevel trains. They are using a laser beam to check the tunnel for objects that might impede passage of double-deckers, Brucker said.

The survey is expected to be completed by this summer.

The DOT, which supplies the equipment used on the Metro-North line between New Haven and New York City, is also awaiting results of a separate rail study on double-deckers, said Harry Harris, the DOT public transportation chief.

But it could be years before the cars roll through Connecticut, he said.

“There is no money in the capital budget to even begin engineering a new generation of equipment,” Harris said.

–Associated Press