"Broadway Tube Proposed in '49" (1926)

The New York Times · September 12, 1926

Broadway Tube Proposed in '49

Alfred Ely Beach, Who Devised Shield Method Of Subway Building, Sponsored The Project Then

When Governor Smith of New York and Governor Moore of New Jersey shook hands across the boundary line between the states. one hundred feet below the surface of the Hudson River, on Aug. 21 last, in official celebration of completion of the Holland tunnel, they celebrated at the same time the anniversary (which really was ten days later) of the birth of Alfred Ely Beach, whose invention of the tunneling shield fifty-eight years before made possible the construction of the twin tubes, twenty-nine and a half feet in diameter and 9,000 feet long. These vehicular tubes are the largest in diameter that have thus far been driven, being more than three time the diameter of the original tube that penetrated the earth under Broadway in 1869.

As editor and half owner of The Scientific American, Mr. Beach proposed in his paper in 1849 a subway under Broadway, the cars to be drawn by horses. Something more than a decade later his attention was drawn to experiments being made in England in transporting parcels and mail in pneumatically propelled cars that ran on rails in pipes or tubes of wood laid on the surface of the ground: and, more particularly, to the opening of such tubes running under ground and connecting the London Postoffice with Charing Cross railway station. Lord Stanley, the British Postmaster General, had officiated at the opening of these tubes and had declared them to be a great success and time-saver. Several men had lain down in the cars and been whisked through the tubes along with the mail.

Editor Beach appreciated the advantages of this quick method of transport and decided to work for its adoption in the United States. He forthwith procured from the Legislature a charter good for fifty years, giving him the right to connect the General Postoffice at Broadway and Liberty Street with the substations by means of twin mail tubes four and a half feet in diameter. At Fourteenth Street the main tube was to have a branch under Fourth Avenue, and another tube under Eighth Avenue was afterward provided for.

Doubt of Method's Safety. When it came to digging up Broadway and removing the Belgian block pavement in order to lay the tubes, the city authorities intervened. There was a great hue and cry that the walls of the Astor House would crumble if any such attempt was made. But Beach was not to be deterred. Necessity being the mother of invention, he began experimenting to devise a way to drive his tubes under Broadway without interfering with traffic. Success crowned his efforts in 1868, when he found he could push through the earth by means of screw jacks, a barrel-like affair made up of wood staves through which the earth was removed as the "shield" penetrated the ground. He patented this the following year, and decided that, while he was about it, he would drive a tube of twice the diameter, or nine feet. and put the two four-and-one-half-foot tubes, within it.

What Editor Beach had in mind was a full-sized subway to carry passengers. He had demonstrated the feasibility of this idea by means of a car with an open-top and piston ends. which ran in a wooden tube six feet in diameter. Such a tube was constructed, suspended from the wall of the Fourteenth Street Armory during the American Institute Fair that was held in this building in 1867, and was shown in operation. The tube was 107 feet in length and the car was drawn through it by suction and pushed back again by the blast of air from an ordinary eight-blade air propeller ten feet in diameter, which was driven at the rate of 250 revolutions a minute by a fifteen-horsepower steam engine. Anyone who has experienced the blast of air from a modern airplane propeller can understand how, when the air is confined in a tube or wind tunnel, it could easily drive a car at high speed before it. This demonstrating tube and the car were constructed of veneer in six weeks' time. The car was on whees and ran on rails. There was also a smaller tube with an open top car that, as it passed below a letterbox, turned a sort of X-shaped wheel into which the letters had dropped, thereby dumping them into the car collecting them automatically and depositing them in the same manner in the postoffice. More than 170,000 people were given a ride In the passenger car, and Mr. Beach, for the second time, was awarded the Gold Medal of the American Institute.

With the small shield constructed of wood a four-and-one-half-foot tunnel had been run out under Broadway some fifteen feet. and had demonstrated that a tunnel could be driven in this manner without disturbing anything overhead, while the shield could be directed or steered around a curve through applying more pressure on the outside of the curve than on the inside by means of the screw jacks.

The next step was to build a shield of sufficient size to make the tunnel he desired to construct. Work was immediately started on such a shield, and it was finally put together and completed in a machine shop on Water Street. In the fall of 1968, this full-sized shield was set up in the cellar of 260 Broadway, at the south-west corner of Warren Street, and was started out on a curve beneath Broadway. The bottom of the shield was about twenty-one feet below the surface of the pavement. The shield worked on the same principle as did the small one, except that in place of hand screws hydraulic jacks were used to force the cutting ring forward through the ground.

The shield consisted of two iron rings connected by wood staves about three feet in length. The foremost ring was provided with a sharp cutting edge and transverse shelves across the front, to prevent the sand from caving inward. Set into the rear ring, which was made of heavy wrought iron, were eighteen hydraulic jacks, placed at equal intervals around the inside; and fastened to the outside of the ring was a metal hood that extended rearward over the wall of the completed tunnel.

The method of operating the shield was as follows: A large hand pump, placed within the shield, was used to force water into the jacks, thus gradually driving out their rams against the end of the tunnel already constructed and forcing the shield forward some sixteen inches. A total pressure of 126 tons was obtained in this simple manner. The thin metal hood, extending back two or three feet beyond the rear ring, was always over the completed tunnel end. As soon as the pressure had been relieved, the rams of the hydraulic jacks were pushed back, or home, and the sixteen-inch head space that had been gained was bricked up. At the same time, workmen dug out the earth at the front of the shield and carried it back through the shield and the completed tunnel.

Six months were required to drive the ninety degree curve out under Broadway and to line it with cast iron plates such as are used in tunnels today. The curve was finished in March, 1869, and the straight part of brick to the south side of Murray Street in time for the grand opening on Feb. 26, 1870.

The tube bad been completed without public knowledge, the earth having been removed at night. Several hundred thousand persons experienced the thrill of a ride at 25 cents apiece.

The proceeds were given to charity as there was no provisions in the charter covering the charging of fares. It was this technicality that finally defeated the four-track subway that was eventually authorized under Broadway.

Although Mr. Beach was not allowed to use steam locomotives, as was subsequently done in the London Underground, or any means of propulsion that would produce noxious gases, the Legislature passed a bill providing for an elevated railway on which coal-burning "dummy" engines were used for many years. The building of this elevated railway was really what blocked the subway project in the 1870s; but ten or fifteen years later, under his charter, Mr. Beach could have constructed an electrically operated subway such as that begun in 1904, had it not been for the technicality that there was no provision in the charter enabling him to charge a fare. The charter was still in force when the 1912 subway was built. Also, the original Beach car and shield that drove through the earth were found intact.