NEW MERSEY TUNNEL.

Press, Volume LXV, Issue 19803, 16 December 1929, Page 5

NEW MERSEY TUNNEL.

ROAD SUSPENDED ON GIRDERS. BIG LIVERPOOL WORK. Deep under the bed of the River Mersey the quaintest roadway ever known has been built. Huge baulks of timber compose the structure, aud for nearly a mile it runs through jagged rocky caverns and between ironclad walls, slung in a cradle expended on girders*. The roadway is but a temporary phase in the construction of the new £". 000,000 Mersev traffic tunnel, which will link Liverpool and Birkenhead with three miles of subterranean roadwavs, aud will be the largest subaqueous tunnel in the world when completed. , Immense ' progress has been made since the late Sir Archibald Salvidge, the promoter of the enterprise, broke through the wall of rock separating the Birkenhead and Liverpool sections under the Mersey eighteen months ago, but so gigantic is the task that it is estimated another three years will elapse before its completion. Day and night the dimly-lit borings echo and re-echo the deafening rumbling of blasting operations, and the machine-gun-like clatter of countless pneumatic drills piercing the virgin sandstone through which the tuniiel is being bored. It is estimated that altogether over 1.000,000 tons of rock will be excavated. Tour Streams of Traffic Originally two loft diameter borings were made, one above the other, and these axe being broken through to form the full-sized tunnel, which is 44ft in diameter, and will accommodate on the main level four streams of vehicular traffic and two footwalks. Provision is being made in the bottom section for two more streams of traffic and side air-ducts for ventilation, through which air will be pumped by plants on either side of the river. The "plants are capable of delivering nearly 4,000,000 cubic feet of fresh air a minute in many places. The full diameter of the circular tunnel is now almost completed, and great sections have been lined, with cast-iron segments or strengthened with steel girders, while other sections are being devoted to experimental work with various types of linings and facings, to ensure the most efficient and economic method being employed. 1920-Ton Load Tests. One small section of the main roadway has been completed in reinforced concrete of from two to one foot thickness, and though it is constructed to carry the maximum load of 100 tons permitted by the Ministry of Transport, tests will be made with loads up to nearly 190 tons before the road is opened to traffic Although in one part under the mid-river only ■ four feet of rock separates the tunnel roof from the clay and sand of the river bed, the employment of the cast-iron, closely-fitting segments, sealed with cement and concrete, prevent any percolation of water through to the tunnel, and few of the workers now find it necessary to wear oilskins while at their task. By the glare of acetylene flares and electric flood-lights their armies are attacking the rock at innumerable faces, perched high on wooden stagings or in shallow cuttings in the rock face. In parts the headings towards the entrances are nearing the street level, and in one, running under Dale street, one of the principal thoroughfares in the city, a massive steel shield, weighing 200 tons, is being erected to support the roof. Constructed on roller bearings, the shield will be moved gradually forward by powerful hydraulic ramsj capable of working at 44801b pressure per square inch.

MOTORISTS' ROAD RIGHTS. COMMENT IN ENGLAND. Motoring organisations and experienced motorists are pleased that a judge- has made it plain that pedestrians have liabilities as well as rights on the road (states the London "Daily Mail" of October 28th). The action, of Judge Lias in Sheffield County Court in awarding damages to a niotor-cyelist against a man who walked against the cycle and threw the driver off is regarded as a timely warning to pedestrians. It has been a bitter complaint among motorists that many accidents are caused by careless pedestrians, or "jay ■walkers," as they are termed in the United States. The case has arisen at an opportune time, for the chiefs of motor insurance companies have been informed that the Government has decided to include compulsory insurance against third-party risks in the forthcoming Eoad Traffic Bill. What has appealed to the careful motorist is the spirit of fairness which is reflected in Judge Lias's judgment. He held that it was as necessary for a pedestrian to keep a look-out as it was for a motorist. Give-and-Take Spirit. An official of the Automobile Association said: "We must remember that the highway belongs to all of us, and there should be a spirit, of give-and-take between the motorist and the pedestrian. The pedestrian must use his rights with discretion, just as the motorist should. "A great many accidents are caused by pedestrians unwittingly. It is to this class of people that the Sheffield case will come as a valuable warning. "We put our trust in the growing motor-traffic sense rather than in drastic penalties such as are imposed in America. Even dogs are acquiring this new sense." Mr Justice Horridge, in charging the grand jury at the Suffolk Assizes, said he was becoming sadly familiar with the charge of manslaughter arising from road accidents. He continued: "It may be an exaggeration to say that the roads of this country are covered with dead and dying, but it is not far off in truth, for one cannot pick up the paper without reading of someone killed on the road."