Back in the 1980's they opened a new commuter tunnel in Philadelphia to connect the Reading and Pennsy trackage. With the opening of the new tunnel and underground station they stopped using the old Reading Terminal. About a half mile of elevated four track railroad still stands in place in Philadelphia waiting for the next train that will sadly never come. The Spring Garden station will board passenger no more. At one time over 350 trains per day graced these rails and now there is a movement in Philadelphia to converet this elevated line into a park. Photos are linked here:

http://tommysphotos.fotopic.net/c835754.html

What's the total distance of unused viaduct?
Given the cost to totally remove the entire viaduct infrastructure, the elevated park does seam like an attractive idea. I understand this topic has been heated at times since it was announced with in the local area on its use, given the cost either way they decide to go with it. Granted the least expensive way to handle (Or not to handle) the situation is how it's being handled right now, abandonment. With as little green space as there is in our city centers and urban areas I feel this could be a green belt of hope and revitalization to the neighborhoods that this old line runs through. Depending on the distance of the elevated line would be interesting to consider a shared right of way, park and walk trails. I know it's not the historically correct use of the viaduct but I think were past that now, maybe running a light rail or trolley line on the remaining single track after or if the linier park is ever acted on. Yeah yeah I know I'm just rambling but this is just an idea, not trying to stir anyone up just throwing things out there.

Here is another link, they sound like a rail to trails groupe.

http://readingviaduct.org/index.html

While the viaduct will not see active trains again, it does seem like some kind of display of Reading electric equipment might be appropriate near the terminal. If well maintained (not an easy situation in this urban environment), it would help to interpret the site's history. Too often, I've seen rails become trails with no recognition whatsoever of the previous history.