Stanislaus, and Tuolumne rivers. In 1863 he built a bridge across the Fraser River, upstream of Yale at Alexandra in British Columbia. Also in 1863, Hallidie married Martha Elizabeth Woods. They had no children. In 1864, he became a United States citizen. In 1865, he gave up bridge building in order to devote himself entirely to his wire rope manufacturing business, which was experiencing increased demand from the silver mines on the Comstock Lode. In 1867, Hallidie invented the Hallidie ropeway, a form of aerial tramway used for transporting ore and other material across mountainous districts, which he successfully installed a number of locations, and later patented. Cable cars Accounts differ as to exactly how involved Hallidie was in the inception of the Clay Street Hill Railway. One version has him taking over the promotion of the line when the original promoter, Benjamin Brooks, failed to raise the necessary capital. In another version, Hallidie was the instigator, inspired by a desire to reduce the suffering incurred by the horses that hauled streetcars up Jackson Street, from Kearny to Stockton Street. There is also doubt as to when exactly the first run of the cable car occurred. The franchise required the first run no later than August 1, 1873, but at least one source reports that the run took place a day late, on August 2, although the city chose not to void the franchise. Some accounts say that the first gripman hired by Hallidie looked down the steep hill from Jones and refused to operate the car, so Hallidie took the grip himself and ran the car down the hill and up again without any problems. The named engineer of the Clay Street line was William Eppelsheimer. However, Hallidie's previous experience of cables and cable haulage systems make it likely that he contributed to the design of the system. The Clay Street line started regular service on September 1, 1873, and was a financial success. In addition, Hallidie's patents on the cable car design were stringently enforced on cable car promoters around the world and made him a rich man. Other activities Hallidie occupied many positions in San Francisco society. He served as a regent of the University of California from 1868 until his death, and as a trustee and vice-president of the San Francisco Mechanics Institute in 1864 and president from 1868 to 1877 and from 1893 to 1895.