LIVERPOOL AND BIRKENHEAD TO BE CONNECTED BY A 44-FOOT WIDE “TWO-DECKER” The construction of the world’s largest tunnel beneath the Mersey estuary, connecting Liverpool and Birkenhead, was inaugurated by Princess Mary recently, when work was begun on the boring of a vertical shaft in the old dock excavation, seen just in front of the conspicuous Liverpool Dock Offices in the picture. The tunnel—a section is inset-is to have an inside diameter of 44ft. as compared with Rotherhithe’s 27, and the Hudson River twins, each 26, the next largest. It is to cost nearly five millions, and will relieve the acute traffic congestion on the existing ferries, which carried 745,000 vehicles and 62,000,000 passengers in 1923. The chief engineer, Mr. Basil Mott, M.Inst.C.E., does not anticipate any special difficulties, as the Mersey Tunnel construction of 1879-86 indicates that sandstone only will be encountered throughout. Two smaller tunnels will first be driven from shaft to shaft, one of 15ft. diameter in the upper half of the final section, the other of 12ft. below. The curved approaches have an easy gradient of 1 in 30. More than half the cost will be borne by the Treasury. —Drawn by S. W. Clatworthy, for “The Sphere.”

Dominion, Volume 19, Issue 237, 21 June 1926, Page 5

LIVERPOOL AND BIRKENHEAD TO BE CONNECTED BY A 44-FOOT WIDE “TWO-DECKER” The construction of the world’s largest tunnel beneath the Mersey estuary, connecting Liverpool and Birkenhead, was inaugurated by Princess Mary recently, when work was begun on the boring of a vertical shaft in the old dock excavation, seen just in front of the conspicuous Liverpool Dock Offices in the picture. The tunnel—a section is inset-is to have an inside diameter of 44ft. as compared with Rotherhithe’s 27, and the Hudson River twins, each 26, the next largest. It is to cost nearly five millions, and will relieve the acute traffic congestion on the existing ferries, which carried 745,000 vehicles and 62,000,000 passengers in 1923. The chief engineer, Mr. Basil Mott, M.Inst.C.E., does not anticipate any special difficulties, as the Mersey Tunnel construction of 1879-86 indicates that sandstone only will be encountered throughout. Two smaller tunnels will first be driven from shaft to shaft, one of 15ft. diameter in the upper half of the final section, the other of 12ft. below. The curved approaches have an easy gradient of 1 in 30. More than half the cost will be borne by the Treasury. —Drawn by S. W. Clatworthy, for “The Sphere.”