On March 20, 2007, upon completion of preliminary engineering, the MTA awarded a contract for constructing the tunnels, a launch box for the tunnel boring machine (TBM), and access shafts to S3, a joint venture of Schiavone Construction, Skanska USA Civil, and J.F. Shea Construction. A ceremonial groundbreaking took place on April 12, 2007, at the 99th Street tunnel segment built in the 1970s. Actual construction work began on April 23, 2007, with the relocation of utility pipes, wires, and other infrastructure, which took 14 months.