The green, or ‘Pittsburgh’, line depicts the proposed double-stacked route.
The orange, or ‘Mon Line’, shows where double-stacked trains run currently.
The callouts are the pinch points where Norfolk Southern wants to raise the vehicular bridges and the roads leading up to the bridges.
Norfolk Southern justifies the need for adapting the Pittsburgh Line through the densely-populated city because they’re concerned about landslides on their current Mon Line around the city.