A long-debated rail trail in Bucks County that would run along eight miles of unused SEPTA track could move forward or hit a dead end when a holdout township votes Wednesday on an engineering study of the project.

Northampton Township supervisors must approve the study, or the proposed $4.8 million Newtown Rail Trail could be kaput. The other four municipalities through which the trail would run - from Newtown Borough to Upper Southampton Township, along the former Fox Chase-Newtown line - have indicated their support for the project.

The Northampton stretch is a key part of the trail. At 4.5 miles, it is the longest segment, and there are a few hundred homes nearby, according to an estimate by Larry Weinstein, chairman of the Board of Supervisors.

The Newtown Rail Trail would link to Montgomery County's 5.4-mile Pennypack Trail, extending a regional path for bikers and walkers and adding another piece to a far larger initiative known as the Circuit, whose ultimate aim is to connect the Philadelphia region through 750 miles of trail.

While hundreds of miles of trail already crisscross Southeastern Pennsylvania and South Jersey, the Newtown trail is unlike anything Bucks has attempted, county planner Paul Gordon said.

The county said it plans to pay for the project through grants.

Like other trails, the Newtown trail is hailed by advocates as a healthy and potentially commute-changing development. Opponents worry about crime, trespassing on private properties, disruption of wildlife, insurance problems, law enforcement costs, and a lower quality of life for neighbors.

"They're telling you it's all going to be rainbows and lollipops and sunshine. They don't tell you that it's going to be within 20 feet of people's houses," said Bruce Stamm, president of the Jordan Corners Homeowners Association, which includes 34 houses and a swath of private property that abuts the trail. "It's a selfish want, not a need."

The Northampton vote on the study this week will follow months of delay. Meanwhile, engineering has begun in Upper Southampton, and Montgomery County is planning to build a final segment to connect the Pennypack to the Newtown trail at the Bucks County line.

Northampton Township supervisors and some residents still have dozens of questions, said Weinstein, who estimated board members have heard up to 10 hours of public comment.

"We certainly want to hear about where the county is with doing anything to help protect [or] lessen the impact . . . on some of our neighbors," said Weinstein, adding that he had not made up his mind on the matter.

The engineering study would answer questions about issues such as access points, security, and emergency vehicle access, said Gordon, the county planner.

"This would just be the next step in the overall project," he said. "The county's not going to come in and build this trail without the approval of the municipalities."

In Montgomery County, residents had similar concerns before the Pennypack Trail opened, but the trail has not attracted trouble and has become immensely popular, said Jody Holton, executive director of the county Planning Commission.

"A lot of people were concerned about maybe crime, but that hasn't come to fruition," she said. "These projects turn out to be great amenities for the community."

The Bucks County project has gained passionate support from walking and biking advocates, such as the volunteer group Bike Bucks County.

"It's not just a trail," said Ken Boyle, Bike Bucks' chairman. "It is about making a real change to the central part of Bucks County by having this safe alternate means of transportation across the county."

If the study goes forward, the municipalities will still have a final vote on approving the trail.

"I certainly support the concept wholeheartedly," Weinstein said. "The question that myself and the rest of the board members have to figure out is, is this the right place?"