The Insanely Expensive Second Avenue Subway Explained

The boring machine, nicknamed "Adi," sits in the southbound tunnel at 96th Street, 2011. (Jake Dobkin/Gothamist)

Empty platform at 96th Street, days before the Second Avenue Subway is expected to open. (Gretchen Robinette/Gothamist)

The face of "Adi." (Jake Dobkin/Gothamist)

Excavation site for 72nd Street station, 2012. (MTA)

Second Avenue Subway Groundbreaking, 10/27/1972; NYCTA Photograph Unit Collection. (Courtesy of New York Transit Museum)

Structural supports line the walls of the northbound tunnel, 2012. (Jake Dobkin/Gothamist)

Workers in the tunnel at 86th Street, 2013. (Evan Bindelglass/Gothamist)

Digging at the 86th Street tunnel, 2013. (Evan Bindelglass/Gothamist)

Northbound tunnel at 86th Street, 2013. (Evan Bindelglass/Gothamist)

72nd Street station, 2013. (Patrick Cashin/MTA)

Nearly finished tunnel, 2015. (Christian Hansen/Gothamist)

Stairwells under construction at 86th Street, 2015. (Christian Hansen/Gothamist)

Glass pavilion over 96th Street station. (Gretchen Robinette/Gothamist)

Onwards and upwards.(Gretchen Robinette/Gothamist)