AUBURN — The City Council moved ahead Monday night with its support of using the inactive St. Lawrence & Atlantic Railroad between Auburn and Portland as part of a proposed 72-mile multiuse trail system.

A resolution passed 6-1 by councilors supports a proposal that would turn the line into an “interim trail,” meaning the tracks and ties would be removed and converted into a trail, while the corridor would remain available for possible future rail use.

The Casco Bay Trail is a proposed 72-mile off-road trail loop connecting Portland, Lewiston, Auburn, Brunswick and Freeport.

A major part of the loop is a section of the St. Lawrence & Atlantic Railroad known as the Berlin subdivision, which runs between Danville Junction in Auburn and the future site of The Roux Institute in Portland.

Rail advocates have maintained that once the tracks are removed, it is highly unlikely the corridor would again be used for rail, and that building a trail alongside the rail line, or “rail with trail,” would preserve the potential future use of the line.

Initial estimates have said building a trail next to the rail line is estimated to cost $100 million, while building a trail on the rail bed would be roughly half that.

During public comment, a majority of people spoke in favor of the “interim trail” option, particularly cyclists who see the Casco Bay Trail proposal as a “massive recreational asset,” and one that would bring economic activity to cities along the trail.

Several said roads are becoming increasingly unsafe, and that off-road trails would be beneficial for cycling or walking.

Dick Woodbury, who has supported efforts to create an East Coast Greenway trail, said he has “gone to bat” to include the Lewiston-Auburn connection as part of the trail effort. But, he said “it’s much harder without the embrace of this community.”

Woodbury also argued that a parallel track that runs between Lewiston-Auburn and Portland, which is already used for freight, is more feasible for passenger rail, and that the St. Lawrence line should be prioritized for trails.

During the discussion, one rail supporter said if the rail line comes up, “it’ll never come back.”

“Whatever value it has in the future will be gone,” he said. “That’s a big gamble.”

Prior to a vote, councilors said the interim trail option has the greater likelihood of receiving funding, and therefore a more immediate impact.

Councilor Adam Platz said that within the Portland to Auburn Rail Use Advisory Council’s own study, 88% of people surveyed supported the interim trail option.

Mayor Jeff Harmon, who has been outspoken against the “rail with trail” option, said the interim trail is the “only viable path forward to receive some benefit from this asset.”

Councilor Belinda Gerry provided the lone vote in opposition.

The resolution is only a symbolic support of the proposal, which Harmon said will be taken up by the Maine Legislature. Even if the Legislature supports the plan, he said, it would still need to appropriate funding for engineering, and then eventually construction.