This control tower and gate are located on the Pyrmont Bridge, a swing bridge over Cockle Bay in Darling Harbour. The bridge was designed by Percy Allan and opened to traffic in 1902. It was one of the largest spanning swing bridges in the world and one of the first to be powered by electricity. It was closed to traffic in the 1980s when freeways south of Cockle Bay were built but reopened as a pedestrian bridge with the redevelopment of Darling Harbour in 1988. The bridge also carries an elevated monorail which travels between the central business district and Darling Harbour. The monorail track rests on a pivot that allows the track to remain stationary while the bridge swings underneath, so that the monorails can continue to cross even when the bridge is opened for large boats and yachts.