Some of the structure for widening Central Park Blvd. bridge is already in place.

The start of construction to widen the Central Park Blvd. bridge over the A Line rail corridor has been delayed to early spring. With an estimated 12 months of construction, the opening of a widened bridge is now more than a year away. The project was originally slated to begin in November; however, the city and RTD have been searching for ways to minimize closure of the commuter and freight rail operations that will be required when construction activity occurs close to the overhead power lines that serve the A Line.

One option was to construct an “isolation switch” that would minimize the length of a “bus bridge” that would be activated when overhead power lines have to be shut down for worker safety. The bus bridge simply substitutes bus service for the A Line service, meaning commuters would be ferried by bus to the next station, where they can resume their trip by rail. Without an isolation switch, the bus bridge will be required for all commuter rail service east of the 40th and Colorado station out to DIA.

RTD spokesperson Laurie Huff said, “RTD asked Denver Transit Partners [RTD’s A Line concessionaire] to prepare a proposal to install an overhead power sectionalizing switch to facilitate the bridge construction with a shorter bus bridge. The agency prepared an internal cost estimate, and it received an estimate from DTP for that work that was economically unfeasible because it was several times the amount of the internal cost estimate. RTD decided along with Park Creek Metro District (PCMD), which is building the bridge, to decline DTP’s proposal and proceed with the longer bus bridge.”

(PCMD is the special district responsible for regional infrastructure construction in Stapleton.)

PCMD spokesperson Tom Gleason says the number of A Line shutdowns “has not been determined but estimates are no more than 20 will be required.” Huff anticipates the line closures and bus bridges will take place mainly at night because of longer headways (fewer trains) and to take advantage of the window between 1:30 and 3:30am when trains are not running. She said freight traffic will be restricted during construction activities over the Union Pacific tracks “but probably will not require complete shutdowns because they don’t have the overhead power issues that RTD has.”

The $8.4 million bridge-widening project will complete the last 0.65 mile of planned improvements for Central Park Blvd. The new section will be a mirror image of what exists now, i.e., two lanes of southbound traffic plus a wide multi-use path. In addition to providing more roadway capacity, it will eliminate the lane shifting that has been required on the approaches from 36th and 40th avenues.