The proposal would extend the Norristown High-Speed Line from Center City to the King of Prussia mall and office park area, either via Route 202, along a Peco easement south of 202, or a combination of the Peco easement and the Pennsylvania Turnpike.
No matter which option is chosen, Comati said, "this is a project that easily will be half a billion dollars."
Ground-level tracks tend to be less expensive, but take up more space and require extensive relocation of utility lines. They also unleash a host of requirements for pedestrian safety, signal crossings, and other issues. And instead of an electrified third rail, they would require overhead power lines.
Ground-level trains would not share the road with cars, as the trolleys do in West Philadelphia. Instead, they would run along the center of Route 202 in a dedicated right-of-way.
The elevated line would look similar to the AirTrain that goes to John F. Kennedy International Airport in New York City. That track is narrow and runs roughly 20 feet above a six-lane highway.
Ernest W. Churchville, an engineering consultant from Upper Merion, argued that an underground route would be less disruptive and would reinforce the ground in a region long plagued by sinkholes.
"If we had the budget for underground, I would agree," said Liz Smith, a SEPTA planner.
One of the biggest drawbacks to the ground-level option is that it would reduce Route 202 from four lanes to two. King of Prussia already faces thick traffic congestion, and has no public transit other than buses - which are subject to even worse congestion on the Schuylkill Expressway.
"I like the Peco/turnpike idea personally," said Chris Huhn, an Upper Merion resident. With all the development on Route 202 over the last decade, he said, the township went to great lengths to make it more accommodating for pedestrians.
"There's a lot more sidewalks, there's more landscaping down the middle. Losing all that to an overhead rail just seems like it's totally cross-purposes to what [the township has] tried to do," Huhn said.
The project is in the early planning stages, and no decisions have been made on the number or location of stations or parking structures.
Comati said the project is designed to maximize the chances of receiving federal funds. It would be at least nine years before the extension is operational.
At the next meeting, to be held this fall, SEPTA will present ridership projections and cost-benefit analyses on the various routes.