The 7.2km line will branch off the Norristown High Speed Line (NHSL) north of Hughes Park station and follow the Pennsylvania Turnpike on an elevated alignment with five stations, two of which will serve the King of Prussia mall.

The branch will be served by direct trains from both of the current terminus stations of the NHSL, 69th Street in Upper Darby and Norristown.

KOP Rail will provide an improved transit link between Philadelphia’s three main economic hubs – King of Prussia, the city centre and University City.

Septa says KOP Rail will reduce the journey time between central Philadelphia and King of Prussia by 30 minutes.

The project is estimated to cost $US 1-1.2bn and ridership on the branch is forecast to reach 9500 passengers per day by 2040.

Septa will submit the project's locally-preferred alternative to the Delaware Valley Regional Planning Commission for inclusion in the regional long-range Plan. The Final EIS is due to be issued next year.