SCIENTIFIC AMERICAN, New York, March 5, 1870

• Very 1st NYC subway opens w/ prints

Inside has an interesting article with 8 illustrations concerning: "The Pneumatic Tunnel Under Broadway, N.Y." which was a short subway system which preceded the "first" New York subway system by 30 years.
It is the back story which is intriguing. Alfred Ely Beach, inventor and editor of Scientific American, had designed a pneumatic (air-driven) system which he demonstrated at the American Institute Fair in 1867, and he thought it viable for transit operation in underground tunnels. He applied for a permit from the Tammany Hall city government, and after being denied by the corrupt Boss Tweed machine, decided to build the line in secrecy, under the guise of creating postal tunnels, in an attempt to show that subterranean transit was practical. The Beach tunnel was constructed in only 58 days, starting under Warren Street and Broadway, directly across from City Hall.
This issue in Beach's own publication graphically illustrations the operation of his subway system.