[Tunnel construction.]
[Constructing the McAdoo Tunnel.]
[Construction of the Pennsylvania Railroad tunnels under the Hudson.]
[McAdoo Tunnel.]
[North tunnel shield.]
[Holland Tunnel.]
Southbound express tunnel.
Original Exhibits of Rapid Transit Subway Construction Company, Plaintiff [Excavating a tunnel; subway construction.]
Queensboro Tunnel.
Typical Pressure Tunnel Construction Shaft [Catskill System.]
Midtown Tunnel under Hudson River, April 24, 1935
Shaft No. 4, Steinway Tunnel.
[Subway tunnel.]
[Lincoln Tunnel Third Tube.]