Jamie Kendrick, deputy director of the city's Department of Transportation, said federal funds alone won't restore the bridge.
"We would expect for the proponents of the project to pay a significant role in funding the project," he said. "In order to move forward, it's going to have to be a public-private partnership."
Turner said his company sees the project as a partnership, too. He said Turner Development Group has already kicked in $20,000 to $25,000 for an engineering study of the bridge and a like amount for a preliminary design.
Historical records show the span, originally known as the Spring Garden Bridge, received construction approval from the Corps of Engineers in 1903 as part of the Western Maryland Railroad. The bridge is now owned by CSX, but the nonprofit Trust for Public Land has negotiated a purchase agreement, according to Kendrick.
He added that besides tying in with the Westport development, the bridge and trail would provide an amenity for future waterfront development in the west Port Covington area.
CSX spokesman Bob Sullivan said the railroad supports the concept.
"Certainly we're supportive of rails-to-trails projects as a way to keep these corridors intact," he said. "It will be good to see it be part of this project."
Turner noted that the bridge is relatively wide, having been built to carry two trains.
The Westport Waterfront project, just south of the bridge's western end, will include condos, townhouses and a hotel in addition to shops and restaurants. According to Turner, the current Westport light rail station will be rebuilt to let out directly into the new development.
The trail would run along the waterfront in front of the Westport project. Turner said he expects the development to include bicycle and kayak rental facilities.
Bill Eberhart, chairman of the Gwynns Falls Trail Council, said the bridge and Middle Branch trail would be a welcome complement to the existing, more linear trail system.
"People always like loops," he said. "You don't have to double back. You can start at Point A and go back to Point A."
Eberhart said that converting the unused bridge to hiker-biker use would not be an easy task.
The span still has railroad tracks on it and is not safe to walk on, he said. "It's not a simple project, which is why it's probably somewhat expensive to do."
