The subway-line-extension project nears completion as the team prepares for two final blasts, but mechanical failures slow progress; and at the east-side site the mole derails, forcing workers to use hand tools.
The roadheader is used at the east-side access, but it breaks through a waterline; at the west side, a worker doesn't show up, and an inexperienced young sandhog has to fill in; and at the No. 7 subway site there's tension between a father and son.
A mole malfunctions at the Croton Filtration site's upper tunnel and forces the workers to use it without a navigation system; a rookie makes an error; a worker is injured by the jackleg drill; and a risky double explosion is attempted.
Two tunnels are joined beneath the Croton Filtration Plant; and tension escalates when the crew is pushed too hard and a fight erupts. Also: a controlled explosives detonation at a subway-extension site.
Efforts to complete a water-filtration plant has workers using a "mole" that bores through rock and dynamite in another area in the opener of a reality series following New York City's underground construction workers.