The analysis will be similar to a study the state did a few years ago on the Danbury branch, said Carmine Trotta, assistant director of intermodal planning for the Department of Transportation.

The study will look at possible infrastructure improvements, ways to increase ridership, station accessibility, bus connections to stations and parking, Trotta said.

"We're looking at what are the current needs," Trotta said. "We'll look to see what things would look like 20 years out if we did nothing but maintain the system, and what would happen if we made some changes."

The New Canaan and Waterbury branches are starkly different. Both connect to the main New Haven Line, but the New Canaan branch carries about 2,500 passengers at New Canaan, Talmadge Hill, Springdale and Glenbrook stations, and the Waterbury branch serves about 200 passengers at Waterbury, Naugatuck, Beacon Falls, Ansonia and Derby-Shelton stations.

The New Canaan branch runs on overhead catenary power and runs throughout the day. The unelectrified Waterbury branch runs on diesel power, with gaps as long as three hours between service.

Because of the differences, some rail advocates said it's wasteful for the state to study both.

"It's apples and oranges," said Rodney Chabot, a New Canaan resident and past chairman of the Connecticut Rail Commuter Council. "The New Canaan branch is fine. (The state) continues adding more through-trains. . . . Its only need is more service."

But Trotta said it's worth studying both branches equally to see where they could be improved.

"There is a potential to attract new riders," he said of the New Canaan branch. "We don't like to presume what needs to be done. We'll start from scratch."

The State Bond Commission approved the money for the study last year.

The DOT will continue to work with the study's advisory committee, Trotta said. A contractor could be selected within the next few months, and the study could start next year, he said.

The state expects to post a Web site with information about the study and announce a schedule for public hearings in the coming months, Trotta said.