The old line, which still is used occasionally by Conrail, follows the meandering Schuylkill from Philadelphia to Pottstown, then continues on to Reading.
Planners are eyeing the stretch west of Norristown, which links the Montgomery County seat with the older boroughs of Royersford, Phoenixville in Chester County, and Pottstown.
Though the idea is still in its earliest "feasibility" stage, Nelson and others are hopeful that it will spur redevelopment in those boroughs, save open space and ease automobile commuting in a region that suffers tremendous traffic snarls in and around King of Prussia.
The Delaware Valley Regional Planning Commission says towns along the corridor, such as Limerick and Upper Providence, likely will see some of the heaviest development pressure in the Philadelphia region over the next 20 years.
In recent weeks, county planners backed away from the futuristic idea of building planned communities along Route 422 that would be linked by mass transit. Local officials simply weren't interested.
Nelson said it was too early to say what the reaction would be from the affected towns this time around because township officials won't get the details until next week.
But the concept has strong support from some planning advocates.
"It's an excellent idea, exactly the right approach," said Joanne R. Denworth, president of the Pennsylvania Environmental Council. "It may revitalize these communities, add residents and retail and commercial uses and make them more viable, instead of abandoning them for sprawl development."
A county-funded $40,000 study will begin in January to determine where stations might be located and what types of land use and zoning would best promote ridership.
Nelson said it was likely that areas near the proposed stations would include residential and retail space, offices, light-industrial plants and possibly some civic uses, such as libraries and recreation centers.
"You can't open a transit line and magically have all the riders you need," Nelson said. "The land uses have to be compatible."
The study, expected to be completed by the summer, also will determine what population densities are necessary to make the rail line work. If that is favorable, the county would then study construction and operating costs and other factors.
Though the plan has some momentum, it is battling a headwind driven by market forces.
For instance, most commercial development is occurring right beside Route 422, which runs parallel to the rail line one to two miles to the north. Though it is possible that buses could link those businesses with the rail line, studies show that regional ridership falls dramatically when commuters must transfer from one service to another.
"Right now, the jobs are not in the boroughs, but up along 422," Nelson said.
The line also misses the core of King of Prussia by about two miles, but could merge with a potential rail loop now being considered by Upper Merion Township.
"When we were trying to sell the (village transit) idea, many people said, 'Why don't you look at the existing line,' " Nelson said. "So that's what we're doing.
"It has all the good advantages like revitalizing old towns, saving the countryside from sprawl, reducing air pollution, all the good stuff planners like to talk about. Unfortunately, we know the world doesn't always work with these clean ideals."