NEW BRIDGE IN SCOTLAND

Press, Volume LXXII, Issue 21975, 26 December 1936, Page 9

NEW BRIDGE IN SCOTLAND

AUTOMATIC CONTROL PHOTO-ELECTRIC CELL USED LONDON. December 1. The new road bridge across the Firth of Forth at Kincardine, which cost £350.000, is believed to be the first instance of the application of photo-electric cells to bridge control. In the centre of the bridge is a swing span 364 feet long and weighing 1600 tons which rotates on a central pier; this provides two clear openings for shipping each 150 feet wide. The whole of the control gear, together with the traffic control, warning devices, and the complete lighting of the bridge was designed and manufactured by the General Electric Company, Ltd., of England. The actual driving mechanism is installed in a machinery room between the I’oadway and the drum girder, and it is controlled from a cabin 30 feet above the roadway in the centre of the swing span. When the span is moved into the “Ihrough road” position it is accurately aligned by moans of special photo-electric cell equipment, in conjunction with automatic indicating devices. The operator’s desk in the control cabin is the nerve centre of the Installation, for on it are mounted the main control hand-wheel, various master switches and push buttons, and 37 indicating lamps; a dial shows the position of the swing span at any point in its travel through 90 degrees. As soon as the operator in his cabin sees that a ship is waiting to pass through the bridge, he turns the main control hand-wheel, and the electric control equipment automatically takes entire charge and performs all the operations necessary to open the span, without any further action by the operator. First of all, the traffic lights on the bridge change to red and warning bells ring; after a short interval traffic barriers are lowered at each end of the swing span, while in the meantime a siren warns the wailing vessel that the span is about to open. Then the largo steel bolts and wedges locking the span in position are drawn, and slowly the span rotates into the open position.