page_title: Queens–Midtown Tunnel
section_title: Construction
hierarchical_section_title: Queens–Midtown Tunnel / History / Construction
caption_attribution_description: Queens Midtown Tunnel to LaGuardia Airport
context_page_description: The Queens–Midtown Tunnel is a vehicular tunnel under the East River in New York City, connecting the boroughs of Manhattan and Queens. The tunnel consists of a pair of tubes, each carrying two lanes. The west end of the tunnel is located on the East Side of Midtown Manhattan, while the east end of the tunnel is located in Long Island City in Queens. The tunnel carries Interstate 495 for its entire length; I-495's western terminus is at the Manhattan portal of the tunnel.
  The Queens–Midtown Tunnel was first planned in 1921, though the plans for the tunnel were modified over the following years. By the 1930s, the tunnel was being proposed as the Triborough Tunnel, which would connect Queens and Brooklyn with the east and west sides of Manhattan. The New York City Tunnel Authority finally started construction on the tunnel in 1936, although by then, the plans had been downsized to a connector between Queens and the east side of Manhattan. The tunnel, designed by Ole Singstad, was opened to traffic on November 15, 1940.
  The Queens–Midtown Tunnel is owned by New York City and operated by MTA Bridges and Tunnels, an affiliate agency of the Metropolitan Transportation Authority.
context_section_description: The Tunnel Authority approved plans for the Queens–Midtown Tunnel in August 1936, and the Authority's chief engineer, Ole Singstad, was tasked with the project's design. By the end of the month, the first bids for the tunnel were advertised. A groundbreaking ceremony for the tunnel was held on the Queens side on October 1, 1936, with President Franklin D. Roosevelt in attendance. Shortly afterward, the New York City Tunnel Authority awarded the first contracts for the tunnel's construction. Test bores for the tubes were started later that month. These exploratory bores utilized diamond-tipped drills operated from flat-bottomed boats, which drilled downward into the riverbed.
  After the test bores were completed in November 1936, engineers determined that there were many geological and manmade obstacles to constructing the tunnel. First, the Queens–Midtown Tunnel's path passed through a large concentration of solid rock, although there were also some pockets of dirt under the river that would be easy to dig through. Additionally, sandhogs digging the Queens–Midtown Tunnel would have to avoid accidental damage to the East River railroad tunnels to the south and the Steinway Tunnel to the north. Of the four shafts that were being constructed for the tunnel, only the Queens construction shaft had been completed. The next month, the Tunnel Authority had accepted a bid for the Midtown ventilation shaft, and it had been authorized to begin the shaft's construction immediately. Construction on the Manhattan ventilation shaft began with a ceremony on December 31, 1936, and four months later, the city bought the entire city block surrounding the shaft was located.
  The first $500,000 allocation of PWA funding was released in January 1937. A 40-foot-deep (12 m) layer of clay was placed at the bottom of the East River, atop the tunnel's path, to prevent air leakages and to maintain air pressure within the tubes. This "blanket" contained about 250,000 cubic yards (190,000 m³) of clay. This was the first time a clay blanket was used on an underwater tunnel project, so digging work was delayed for four months to allow the clay layer to be placed. Officials feared that the tunnel might not open before the end of 1940, as was originally planned. A contract for digging the tubes themselves was awarded in June 1937. The project employed as many as 2,500 sandhogs at a time. Because the work site had such a high air pressure, each man worked two 30-minute shifts per day, punctuated by a 6-hour break in a depressurized chamber so that they would not get decompression sickness.
  On the Queens side, it was proposed to link the tunnel to what is now I-495. Eventually, officials agreed to construct the 2.5-mile (4.0 km) link to what is now the Brooklyn-Queens Expressway, forming part of a longer highway that connected directly to LaGuardia Airport. The status of a corresponding limited-access expressway on the Manhattan side, connecting to the Lincoln Tunnel, was still undecided. The Manhattan entrance and exit ramps replaced the St. Gabriel Church, which later relocated to Park Avenue. By early 1938, costs were rising quickly, and only 65% of the contracts had been awarded. Tunnel Authority Commissioner Friedman stated that if costs were to keep increasing at the same rate, construction might have to be abandoned midway through. By September 1938, three-fourths of the tunnel's contracts had been awarded.
  Work on the underwater section of the tubes started in April 1938. Underwater boring was supposed to have started earlier but the geology of the underwater section had delayed construction. When the underwater digging started, La Guardia opened the valves that allowed compressed air to flow into the tubes, and workers started digging the tunnels under the river from each end. The pressurized air allowed sandhogs to work as much as six hours per day in two 3-hour shifts, but as they tunneled nearer to the center of the river, the pressure increased and sandhogs worked fewer hours per day. Builders also pumped air along the top of the tunnel to preve
caption: View inside the tunnel
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