A new group of business, civic, and academic leaders backing SEPTA's proposed Norristown High Speed Line extension to King of Prussia is portraying the project as a crucial link between the region's largest suburban employment center and Philadelphia's urban core.

The King of Prussia Rail Coalition was formed to promote the extension after the release late last week of a draft report on the project's impact, an important early phase of development. Jerry Sweeney, president and chief executive of Philadelphia developer Brandywine Realty Trust, was named the group's chairman.

The project would branch off the existing line a few stops shy of its Norristown terminus, wending west through about four miles of Upper Merion Township to end near the Valley Forge Casino Resort after stopping at the King of Prussia Mall, the King of Prussia Business Park, and other locations.

With the project's anticipated completion in 2023 at an estimated cost of $1.1 billion, those employment-rich suburban sites would be connected to Philadelphia's main business districts of Center City and University City via the Norristown line's existing link to the Market-Frankford Line at 69th Street in Upper Darby.

"When we look at King of Prussia and the wonders it provides in terms of economic growth … it becomes incredibly important to make sure we do not pass King of Prussia by, that King of Prussia becomes just as accessible as other parts of our region," Sweeney said at a news conference Tuesday announcing the rail group's formation.

The group also includes officials with the Montgomery County Board of Commissioners, the Greater Philadelphia Chamber of Commerce, the King of Prussia District business association, and officials with Drexel University, the University of Pennsylvania, and Villanova University.

The organization was formed ahead of scheduled sessions next month to present the new report, a so-called Draft Environmental Impact Statement, in King of Prussia and Norristown.

When aspects of the proposal were last presented, at the start of 2016, critics said that the planned rail line would pass too close to existing homes, amid other complaints. Since then, a petition by a rail-opposition group calling itself NoKOPRail has attracted more than 800 signatures.

The impact study, released Oct. 13 by the Federal Transit Administration and SEPTA, looks at how each of five potential routes would impact area properties, ease transit use, enable economic development, and other criteria. It also analyzes the consequences of abandoning the project.

The route recommended by the study's authors would follow a portion of an existing PECO electric utility corridor and a strip of Pennsylvania Turnpike property passing behind the King of Prussia Mall, before turning north to use a section of Norfolk Southern Corp. railroad track. It would then turn west along First Avenue to end near the intersection with North Gulph Road, close to the casino resort.

King of Prussia Rail Coalition members say the benefits of the project would be enormous, including increased job growth in King of Prussia of up to 1,500 positions a year and 310,000 square feet of real estate development stimulated along the corridor.

Sweeney, whose Brandywine owns office properties along both existing and proposed portions of the envisioned Center City-to-King of Prussia transit route, called the project "a regional economic imperative."

"We absolutely have to make sure that our mass transit system here really does … create a great framework for businesses to grow," he said.