After years of snafus, political battles, and funding fits and starts, New York City’s next major transit extensions are taking shape.Newly bored caverns deep below city streets and railyards provide hidden testimony to the construction team’s accomplishments, all while the nation’s busiest subway and commuter rail network strains to carry millions of passengers to and from the city. The next tunnels are a study of firsts, many side by side.
Two giant tunnel-boring machines, crawling along like worms underneath the Big Apple, made transit history. Below neighborhoods on Manhattan’s West Side, they both achieved a difficult 90° turn, helped by a ground-freezing technique—the first time TBMs have successfully excavated through frozen ground. A third machine is crawling through steel-braced earth underneath the dense urban development on the upper East Side. In Queens, another TBM is taking shape for more tunnel duty.