The Glasgow, Paisley and Greenock Railway (GP&GR) was an early Scottish railway, opened in 1841, providing train services between Greenock and Glasgow. At the time the River Clyde was not accessible to sea-going ships, and the intention was to compete with river boats that brought goods to and from the city. In fact passenger traffic proved surprisingly buoyant, and connecting steamer services to island resorts in the Firth of Clyde provided a very great source of business.
The GP&GR merged with the larger Caledonian Railway in 1851.
The Greenock station was not alongside the steamer berths and as the trade developed, this became a significant disadvantage.
The independent Greenock and Wemyss Bay Railway built a branch line to a pier at Wemyss Bay, giving much closer access to Rothesay, and in 1889 the Greenock line itself was extended to Gourock.
The work involved the building of Newton Street Tunnel, the longest railway tunnel in Scotland.