An Amtrak Acela Express makes a late afternoon departure from Philadelphia. The cranes within the photo reflect a spate of new skycrapers set to redefine the Philadelphia skyline, including, in the background behind the Acela, the $1.6 billion dollar, 1,121 feet fall Comcast Innovation and Technology Center which will take its place as the tallest building in the US outside of NYC and Chicago when it opens in 2017.