[Tunnel construction.]

[Constructing the McAdoo Tunnel.]

[Construction of the Pennsylvania Railroad tunnels under the Hudson.]

[McAdoo Tunnel.]

[North tunnel shield.]

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.]

[Holland Tunnel.]

[Holland Tunnel.]

Queensboro Tunnel.

Queensboro Tunnel.

Midtown Tunnel under Hudson River, April 24, 1935

[Subway tunnel.]

[Lincoln Tunnel Third Tube.]

[Holland Tunnel.]

Unidentified tunnel.

Shaft No. 4, Steinway Tunnel.

Subway tunnel construction at Lexington Avenue and 97th Street.