New York MTA: No. 7 tunneling on target
Thursday, March 19, 2009, marked the official beginning of the tunneling phase of MTA New York City Transit’s Line 7 subway extension project. With a who’s-who of politicians looking on, MTA Capital Construction lowered a key part of the first of two tunnel boring machines (TBMs) that will excavate two 7,100-foot tunnels. The piece lowered Thursday is known as the cutter head and has 44 rotating discs.