This article was originally published on February 20, 2004.

Coming upon the Reading Viaduct in the Loft District north of Vine Street is a little like stumbling upon some industrial-age Angkor Wat. Its steel rails have all but disappeared inside a jungle shroud. Its immense stones are blackened with soot from factories that the living no longer recall. You sense that this behemoth once belonged to a great civilization, even if its purpose now seems obscure. 
In fact, the decaying commuter-rail trestle was rendered obsolete only 20 years ago by the opening of the train tunnel under the Gallery mall. Other than a short piece that was torn down to make room for the Pennsylvania Convention Center, the viaduct was left standing. Demolition proved too expensive. 
Nowadays, no one in the fledgling Loft District - the neighborhood east of Broad Street between Vine and Spring Garden - would ever suggest getting rid of the viaduct's remaining half-mile. The issue is how to preserve it. 
Nature has already staked its claim, turning the stone-and-steel land bridge into an unlikely, and wildly overgrown, "ribbon park. " The Loft District's urban pioneers, who have been busy with their own reclamation of the area's abandoned factories, want to build on nature's work. 
They aren't yet sure how to proceed, says John Struble, a furniture-maker who recently acquired a former machine shop that cleaves to the side of the viaduct near 11th Street. So Struble, along with painter Sarah McEneaney, have formed a nonprofit group called the Reading Viaduct Project to explore the possibilities. 
McEneaney, who has lived in the Loft District long enough to have boarded trains at the viaduct's old Spring Garden stop, has come to love the trestle as much for its panoramic vistas as for its looming medieval presence. The viaduct frequently appears in her paintings (which are on exhibit at Philadelphia's Institute of Contemporary Art until April 4). 
If you climb carefully up the viaduct, through the thick underbrush, heaps of trash and occasional homeless person's campsite, you soon discover that the railroad aerie offers a view of Philadelphia unlike anywhere else. The towers of Center City gleam on the horizon like a faraway Oz. Somehow the harsh industrial landscape on its fringes makes the viaduct feel like a serene oasis, rather than a gritty outpost. 
Those atmospheric qualities also caught the imagination of the University of Pennsylvania's School of Design. Earlier this month, the school held a four-day brainstorming session to come up with new uses for the old trestle, which runs diagonally from 11th and Vine Streets to 9th and Fairmount Avenue, with a 1,000-foot-long westward spur at Noble Street. 
The Penn design teams were partly inspired by Paris' success in transforming an elevated train trestle near the Place de la Bastille into an elegant, 2.4-mile-long landscaped path called the Promenade Plantee. (Excellent photographs can be found at Such obsolete viaducts are fast being transformed into sky parks in cities around the world. New York City is working on plans to convert Manhattan's High Line, which runs through Chelsea, into an elevated park. 
In Philadelphia, the challenge will be finding government support and money for a park in an area with fewer than a thousand residents. The viaduct will require a thorough environmental scrubbing before it can be opened to the public. By the time the last commuter trains trundled out of the old Reading Terminal in 1984, the viaduct's four tracks were sodden with PCBs and other contaminants. Struble and McEneaney must also deal with the Reading Company, which still owns the viaduct. 
Some of the best ideas that emerged from the Penn brainstorming session were the simplest. One team suggested that the Reading Viaduct Project should start off by installing architectural lighting on the trestle, both to highlight its beauty and to make people feel safer walking around it. Its large, imposing walls could be used to show movies in the summertime. Such events can help raise the viaduct's visibility among Philadelphians. 
McEneaney and Struble are also taking their cues from the success of several local "rails-to-trails" projects. Just as a new Schuylkill river recreation path is expected to lure residents and business to the southeastern edge of Center City, they believe a park atop the Reading Viaduct path could help populate the Loft District. 
But Struble said he sees the viaduct as an amenity for all Philadelphians. "I don't think I should be one to decide what it should be," he said as he picked his way along the tracks in the winter sunshine. "Everyone should think about it."

Contact architecture critic Inga Saffron at 215-854-2213 or