With construction of Warwick’s intermodal project in full swing and on schedule for completion in 18 months, the state has still to finalize an agreement with the Massachusetts Bay Transit Authority to provide rail service, no less build a siding so that trains can “turn around.”

If that has Steven Devine of the Department of Transportation worried he doesn’t show it.

Devine, DOT chief of intermodal planning, said Monday the goal is to have both the service agreement and the Wickford Junction station where the turn around siding will be located in place by the time the $266 million intermodal facility providing a rail to airport connection is open. There are yet more unresolved issues. The state hasn’t reached an easement agreement with Amtrak for the siding as well as a contract with developer Robert Cioe, who owns the site of the Wickford station and proposed adjoining 1,000-car parking garage.

Cioe said this week there is sufficient time for him to build the station and garage to coincide with the opening of the intermodal facility although it would be tight. Devine also believes it is possible.

The cost of the two projects is pegged at $23 million to $24 million with $3 million to $4 million allocated to a mile-long sidetrack. The money, Devine said, has been secured by Senator Jack Reed and would come out of the New Starts funding of the Federal Transit Administration budget.

The MBTA diesel-powered trains would not actually “turn around” after reaching the southerly end of their run at Wickford. Rather, explained Devine, they would stop at the sidetrack to allow the engineer to walk to the opposite end of the train for the return trip month. The turn around takes about 15 minutes.

That could be accomplished without a siding if was not for Amtrak. Amtrak does not want trains stopped on its high-speed rails.

Should the Wickford siding not be completed by the opening of the intermodal facility, Devine says there are options including use of a Quonset side track and stopping the train in Warwick. Both options are less than perfect. The Quonset siding would mean an empty run from Warwick south while the Warwick alternative would require an additional expenditure for a signal system.

While it has not been worked out, Devine said it is possible the MBTA will need to make “deadhead” (empty train) runs in order to initiate the morning service from Wickford and return trains to the overnight facility in Pawtucket at the end of the day. Trains would not be parked overnight at the Wickford siding, he said.

“We’re going to contract for them (the MBTA) to run it,” Devine said. Those funds would be paid by the state regardless of train ridership. The projection is that the eight round trips between Providence and Wickford will carry 1,700 passengers a day. Further, Devine said, the expectation is that 80 percent of the passengers boarding at Wickford would be commuting to Providence with the remaining 20 percent going to Boston. On the other hand, 80 percent of those boarding at Warwick are projected to be traveling to Boston with only 20 percent debarking in Providence.

Devine said fares have not been determined, but it is likely that the Providence to the south service would be treated as a separate zone.

Although according to a Feb. 12 Boston Globe report, MBTA is having difficulty meeting payment on debts of $5.2 billion and is weighing a 25 percent increase in fares and/or cuts in service, Devine doesn’t see those conditions as influencing an agreement to bring service to Warwick and Wickford.

“There is no indication that this project would be impacted by the current financial situation,” he said.

A MBTA spokesperson did not return telephone calls, but by email referred inquiries to Adam Hurtubise of the Massachusetts Executive Office of Transportation.

Hurtubise did not respond to questions about negotiations or issues that need to be addressed for MBTA service to be extended south of Providence.

In an email he said, “We are very interested in improving mobility regionally.

It makes a great deal of sense to get people to and from our commercial airports via public transportation.”

Devine didn’t put any stock in the fact that the MBTA Web site makes no mention of the expanded Rhode Island service in its list of projects either under construction or in planning.

“We’re well beyond the planning stages. We’ve done the design and are entering the construction phase,” he said.

Indeed that is the case of the Warwick station.

Still, however, while there’s an understanding that service will be provided, there isn’t a signed agreement and until there is there won’t be train service here.

Patti Goldstein, Rhode Island Airport Corporation vice president of marketing and communications said yesterday that the intermodal project is on schedule and within budget.