A pair of railway tunnels in Renfrewshire, the Bishopton Tunnels are located on the Inverclyde Line, to the south of the River Clyde and a quarter-mile (0.5 km) northwest of Bishopton. The tunnels extend to 603m / 1980 feet and comprise Bishopton West Tunnel (310m / 1020 feet in length) and Bishopton East Tunnel (293m / 960 feet), with a 91m (300 feet) gap between and deep rock cuttings at both ends. The tunnels came about because of the route chosen for the Glasgow, Paisley and Greenock Railway, necessitated by the local landowner, Charles Stuart, (12th Lord Blantyre; 1818 - 1900), who opposed its construction within sight of his residence at Erskine House (now Mar Hall). Authorised by an Act of Parliament in 1837, the building of the tunnels was a massive civil engineering undertaking, hewn from solid rock by around 2000 navvies over a period of four years, finally opening in 1841. It was said that the cost of the gunpowder alone amounted to £12,000.