The Reading Viaduct Spur took another step toward reality Wednesday morning when the Philadelphia Art Commission gave the project the blessing of final approval.

The Spur is a quarter-mile arm of the viaduct that stretches between Broad Street and Callowhill Street.

Wednesday's presentation described in detail how Phase 1 would incorporate plant material and path surface materials (think chip seal paving) into the project. It also addressed how structural elements (think bridges) would be rehabilitated; how recreational features (benches, swings, lighting) would be strategically placed on the site; how toxins (mostly railroad ballast, very little PCB presence) would be remediated; and how the entire spur would be maintained.

The Center City District is still raising money to complete the planned improvements on the first phase of the project. The group has raised about 65 percent of the $9 million it needs for the "SEPTA spur" and is pursuing a $3.5 million grant from the state's Redevelopment Assistance Capital Program (RACP), according to John Struble, of Friends of the Rail Park. After the improvements are completed, the city would take over ownership of the park.

SEPTA's board of directors must also approve the sale of the property. A spokesman for SEPTA said the sale has not yet been scheduled for a board vote but Wednesday, Center City District CEO Paul Levy said that while SEPTA still owns the land, it will lease it to the Center City District and upon project completion the land will be conveyed to the city's Department of Public Property.

A little background from design firm Studio Bryan Hanes, which is handling the Phase 1 work:

Beginning at grade, the space, approximately 30 feet wide, rises until it becomes entirely supported by structure. Much of the material character of the site comes from the existing structure of the elevated rail line. The design restores and maintains much of the existing steel and introduces materials of a similar industrial scale and character for the platforms, benches and guardrails. The vegetation, too, conveys the rugged character of the place through a richly varied plant palette. Corresponding with soil depth constraints, the vegetation on grade is comprised of woody shrubs and trees. As it transitions to structure, the vegetation becomes less dense and features a lighter palette of grasses and perennials.

It should be noted that programmatically, the spur concept remains simple. A walkway is directed between areas of planting and recreation. Four steel supported wooden platforms accentuate the idea of one feeling comfortable in the site. Their free dimensional surfaces create spaces for lounging and gathering. The main walkway culminates in a series of swings which can be seen from the street below.

The design transforms the neglected railway (but beautiful viewshed) into a vibrant neighborhood park. It becomes a social hub and green space for the area's diverse and growing community, and the city as a whole.

Levy said the public art component of the project is being debated. The PECO substation at 401 N. Broad St. produces quite a bit of ambient noise pollution, so one possible public art choice may be something that screens off that sound. The commissioners were enthusiastic about what they heard concerning Phase 1, but they made it clear they want any art installations to be "appropriate" to the spur.

See more renderings of phase one here. is now a project of WHYY/NewsWorks. It began in 2006 as an initiative of Penn Praxis inside the University of Pennsylvania School of Design. Though now part of WHYY, PlanPhilly still works closely with Penn Praxis in covering planning, zoning and development news.