The state Department of Transportation today approved a $33-million contract with McCourt Construction Co. to start extending the Silver Line from the Airport T stop to Chelsea. Much of the route will be in a busway built along the former Grand Junction railroad:

State officials expect the initial route, from the airport to Eastern Avenue in Chelsea, to be completed in two years.

In the first stage of a multi-phased project, a 1.3-mile long dedicated Bus Rapid Transit lane will be built from just west of the Mystic Mall to Eastern Avenue. The bus-way will be comprised of two 12-foot travel lanes and two 3-foot shoulders. Under the newly approved contract, there will be three new stations built along the bus-way at Eastern Avenue, Box District, and Mystic Mall. The Silver Line stations will have inbound and outbound platforms, and include canopies, shelters, bicycle racks, lighting, signage, fare collection equipment, variable message signs, and closed circuit television cameras.

Once the busway is finished, MassDOT will solicit bids to build a new Chelsea commuter-rail station near the Mystic Mall. And after that will come a Silver Line stop in downtown Chelsea.