DOVER, N.H. – Train service between Boston and Portland is scheduled to begin in less than 100 days, but not a single station or platform has been built.

The lack of construction has some people worrying the long-awaited service will be derailed yet again.

More than 10 years in the making, the “Downeaster” is scheduled to start May 1, on Amtrak’s 30th anniversary, but construction in three New Hampshire towns and four Maine towns hangs on the approval of agreements between Guilford Rail Systems and the Northern New England Passenger Rail Authority.

Attorneys from NNEPRA, which was created by the Maine Legislature to run the service, plan to meet Monday with Guilford’s lawyers at the company’s Billerica, Mass., headquarters.

The rail authority hopes to lease the land in the railroad’s right of way on which the platforms will be built. Guilford sent out platform lease agreements this summer, according to company spokeswoman Cynthia Scarano, but talks since then have failed to produce a final deal.

One bone of contention between the NNEPRA and Guilford is the speed the train will travel. The transportation board ruled in 1999 that the train could travel as fast as 79 mph as long as the track meets certain engineering requirements. Guilford is maintaining those requirements have not been met, but supporters of the service say the speed is crucial to attracting riders.

“It is Guilford’s opinion that the track is constructed for a top speed of 59 mph, in some areas even less,” Scarano said. “Safety being our priority, we want to make sure that if passenger service is going 79 mph, all the structures and facilities meet those requirements.”

Regardless, she said, service still is expected to begin on time.

“Negotiations are ongoing. Nothing is at a stalemate,” she said.

Both the rail authority and Guilford are optimistic that a final lease agreement will be reached Monday.

“It does look like in all probability we’ll have temporary platforms on site by May 1,” said Steve Pesci of the Strafford County Regional Planning Commission.

If platform lease agreements are worked out, construction projects could go out to bid Jan. 30, according to Nancy Mayville of the New Hampshire Department of Transportation. That would allow construction of temporary wooden platforms to begin in early or mid-March, weather permitting.

Any impasse between NNEPRA and the railroad would go to the U.S. Department of Transportation’s Surface Transportation Board.