One of the most challenging aspects of the project will be rehabilitation of the 100-year-old Houston St. Viaduct Bridge, which will carry the proposed streetcar across the Trinity River floodway and connect downtown Dallas with the South Dallas community of Oak Cliff. The Houston St. Viaduct is listed on the United States Register of Historic Places and rehabilitation will require coordination with the Texas State Historic Preservation Office.
HDR says the project will feature several innovations. To avoid placing an overhead catenary system on the historic bridge, the vehicles will feature a battery power system allowing them to run "off wire" for almost a mile as they cross the bridge. It will also feature tram rail, a relatively new type of rail section. Its reduced height minimizes impact to the bridge by adding a thick track slab. It will be only the second project in the U.S. to use this new rail section, an alternative to the foreign-made girder rail no longer allowed on federally-funded projects.
Design is expected to be complete by April 2013. Construction is expected to be complete by June 2014.