For the past 11 years, the Better Philadelphia Challenge has asked university students around the world to address real-world urban design issues in the city. This year, with the first phase of construction well underway, the competition fittingly focused on the abandoned City Branch rail tunnel under Pennsylvania Avenue, asking students to pitch their ideas to transform the space into a recreational and cultural amenity for Philly.
Source: See the winning Rail Park Tunnel designs for the Better Philadelphia Challenge – Curbed Philly