THE PARNELL TUNNEL AN ENGINEERING FEAT.
The new Parnell tunnel is now completed, and it is expected that it will be put into use in about a fortnight's time. Some interesting figures regarding the new tunnel were given to the Star by the District Railway Engineer. The actual work of excavation was commenced on Ist April, 1914, and concluded a few days ago, 25,000 cubic yards of earth having been removed in the eleven months. The tunnel is 1130 feet long, 25ft 9in wide, and 18ft 2in High. The arch is constructed of bricks, in four to six layers, approximately three-quarters of a million bricks having been used. The walls are of concrete, over two feet in thickness. When the tunnel is in use there will be a full double set of rails from Auckland to as far as Penrose. This will mean a very great relief in the pressure of traffic, for at present the single rail which runs through the old tunnel to a great extent diminishes any advantage that is gained from the double sets ot rails on cither side. The completion of the double set of rails will also minimise the danger of accidents, as it will not then be necessary to run both up and down trains on the one , set of rails. The grade of the rails running through the new tunnel is considerably easier than that of those in the old tunnel — a precaution that will do away with the inconvenient habit, that some well- loaded passenger trains have at present, of coming to a standstill in mid-tunnel. The original plans make provision for the installation of electric lights which are automatically switched on and off by trains going through the tunnel, but it is not now certain that this will be done. The old tunnel will not be used by passenger trains, but will only be utilised for communication with the proposed new carriage and wagon buildings at Newmarket. When the tunnel is in use. the old one will not be used at all until these buildings are erected.