CUMBERLAND, Maine — A proposal to extend METRO bus service north of Falmouth hit a second pothole in less than a week Monday, when Cumberland town councilors narrowly rejected an invitation to join the pilot project.

The Town Council voted 4-3 against a resolution pledging Cumberland’s support for a trial bus route that would connect the town with Freeport, Yarmouth and Portland. Council Chairman Tom Gruber and Councilors William Stiles and George Turner voted in the minority.

On Aug. 5, the Freeport Town Council postponed for a month its decision on whether to support the service. In July, Yarmouth’s council voted unanimously to join the pilot project.

The three-year project, proposed in June, would begin in late 2015 and offer express service from the three towns to existing stops in Portland and Falmouth. But first, the Greater Portland Transit District needs the towns’ buy-in.

Participation in the pilot was expected to cost Cumberland $27,000 each year. After that, the town could have opted not to host METRO service, or could have continued it at an annual cost of about $80,000.

The transit district also plans to to seek $675,000-$700,000 in federal funding to pay for the service, according to METRO General Manager Greg Jordan.

For its share of the cost, Cumberland would be home to one or perhaps two stops along the corridor surrounding U.S. Route 1 and Interstate 295, the roads likely to be used by the bus service.

But councilors were skeptical that Cumberland residents would ride the bus.

Councilor Michael Edes predicted “zero participation” by residents, who in effect would be subsidizing the project for riders in other communities.

“I don’t think we could find a bigger misuse of taxpayers’ money in Cumberland than this project,” Edes said. “We’re not going to get any bang for our buck.”

Nevertheless, Gruber, Stiles and Turner said that risk is worth taking. All three noted that the town can choose not to participate in METRO after the pilot if the bus service is unsuccessful.

“It makes sense to go and test the waters,” Gruber said. “We can always get out. And if we don’t at least explore this, we’re cutting ourselves off short.”

Turner said the initial cost of participation is “not a prohibitive number,” and that the town doesn’t have much to lose. Stiles called the pilot “a tremendously good experiment,” although he voiced concern that the bus would stick too closely to Route 1.

“I’m not as happy as I’d be with some loops,” he said, suggesting that the bus venture off the north-south corridor.

Some councilors who voted against the bus also expressed mixed feelings.

Vice Chairman Peter Bingham said he supports regional responses to needs such as transportation, but couldn’t support this one.

“We have bigger priorities,” he said, citing as an example the town’s potential $3 million purchase of beachfront property along Foreside Road, a decision that will be made by voters in a Nov. 4 referendum.

“This just isn’t in my top 10 list of priorities,” Bingham said.

Councilor Shirley Storey-King said she recognizes the need for some mass transit, “but this model isn’t it. The math doesn’t work out for me.”

It’s unclear what Monday’s vote will mean for the proposed bus service.

Previously, Jordan predicted it would be “hard to imagine continuing forward” if one of the three towns didn’t participate. But on Tuesday he was more optimistic.

“We believe we can continue to advance [the pilot project],” he said. “This doesn’t put the project in jeopardy.”

He called the council’s decision “a missed opportunity for Cumberland,” but noted that viable participation by the town was “always a bit of a stretch.” Unlike Falmouth, Yarmouth and Freeport, he said, Cumberland has relatively few businesses or residents along its portion of Route 1.

Meanwhile, he said, METRO is “rescoping” the project to accommodate the participation of only Yarmouth and Freeport.

The revised plan would not call upon either town to pay more, but might result in some service changes. Fewer buses might run during commuting hours, while METRO might add trips at off-peak times.

Originally, METRO proposed running buses only on weekdays, with trips every 30 minutes between 6 a.m. and 9 a.m. and from 3:30 to 6:30 p.m.

Now the ultimate fate of the project may be determined by Freeport, where councilors have already expressed divided opinions about the bus service. If that town does not participate, it will “kill” the project, Jordan has said.

The Freeport council is scheduled to vote Sept. 16.