Queensboro Tunnel.

Queensboro Tunnel.

[Engineers in tunnel during construction of present IRT at City Hall Station.]

Southbound express tunnel.

Subways, Fourteenth Street Cut for Subway, Rock Cut Looking West, Shaft 1.

[Subway tunnel.]

[Digging subway tube under East River for Queensboro Subway.]

P.H. - Template Engine

P.H. - Template Engine

[Tunnel construction.]

Midtown Tunnel under Hudson River, April 24, 1935

Concrete Forms - Engine No. 8

Concrete Forms - Engine No. 8

[Tunnel construction.]

[Queensboro Bridge.]

[McAdoo Tunnel.]

[McAdoo Tunnel.]

[McAdoo Tunnel.]

[McAdoo Tunnel.]

[Holland Tunnel.]