A sky bridge that will connect the new train station, which is expected to be completed by 2010, bottom left, to the T.F. Green Airport terminal.

DOT rendering

PROVIDENCE — The new airport train station planned for Warwick is right on track, a top state official said yesterday at a mutual fund shareholders meeting in Providence.

Site preparation for the station, near T.F. Green Airport, began last month, said Jerome F. Williams, director of the Rhode Island Department of Transportation.

The project’s final design should be finished by December or January, he said. Construction of a parking garage and skywalk at the site should begin in the spring, and the entire project should be completed in 2010, he said.

Williams discussed the train station and other projects in a presentation yesterday morning at the annual shareholders meeting of the Narragansett Insured Tax-Free Income Fund, held at the Rhode Island Convention Center. About 50 people attended.

During the meeting, and in an interview afterward, Williams said that the train station — also known as the Warwick Intermodal Station — will have two main purposes:

•People will be able to travel to the airport by train. (When they get off the train, they will be able to take a kind of moving sidewalk to the airport, which is about 1,250 feet away.) Similarly, people arriving by plane will be able to travel to Providence, Attleboro and other stops by train.

•Commuters will be able to use the train to travel to Providence. (Similarly, people in Providence, Attleboro and elsewhere will be able to use the train to commute to the Warwick area.)

The Massachusetts Bay Transportation Authority, which currently sends commuter trains to Providence, will eventually extend service to the Warwick train station.

This will allow people from Massachusetts, Rhode Island and elsewhere to take the train to the airport.

The station will also serve as a hub for commuters from central and southern Rhode Island traveling to Providence (and for people commuting to the Warwick area).

Both prongs of the project should help reduce highway congestion, Williams said.

“The Warwick Intermodal Station will help provide an alternative form of transportation for the heavily traveled commute that generates from the fastest-growing region of our state — South County,” Williams said in prepared remarks.

Shortly after Williams began his job at the DOT in January, he said he learned that the train station project — originally scheduled to cost about $222 million — would instead cost about $242 million.

In general, the DOT is on the hook to pay for any cost overruns, he said. So the agency took a closer look at the project and found ways to redesign it that will keep the cost at $222 million — without reducing the project’s size or scope, Williams told shareholders at the meeting yesterday.

In an interview afterward, he said, “We don’t have extra money, so we went back, looked at what we could” do to reduce the cost. “It’s not a major redesign.” The agency essentially made “some minor changes,” but none of them will “take away [the project’s] usability, function or number of [parking] spaces,” he said.

As a result of one such change, less of the facility will have to cross over the railroad tracks, so building costs will be lower, he said. Overall, the agency found about $20 million in savings, he said.

The shareholders’ meeting was held as the Narragansett fund celebrates its 15th anniversary, said Diana P. Herrmann, fund president and trustee. Her father, Lacy B. Herrmann, the fund’s founder and chairman emeritus, also attended.

Narragansett is a single-state tax-free fund. In general, the fund uses shareholders’ money to buy Rhode Island government bonds. Interest that the fund receives is passed along to shareholders, in the form of dividends, which are generally free from federal and Rhode Island income tax for Rhode Island shareholders. (For shareholders in other states, the income is generally free from federal tax, not from state tax.)

The fund has about 1,900 shareholders and about $150 million in assets under management, Herrmann said.

Also at yesterday’s meeting, shareholders elected a number of trustees. Besides Herrmann, they include William J. Nightingale, David A. Duffy, Timothy J. Leach, James R. Ramsey, J. William Weeks, and Laureen L. White.

ndowning@projo.com