Bowling Railway Tunnel

The Lanarkshire and Dumbartonshire Railway was a railway company in Scotland. It was promoted independently but supported by the Caledonian Railway, and it was designed to connect Balloch (on Loch Lomond) and Dumbarton with central Glasgow, linking in heavy industry on the north bank of the River Clyde. From Dumbarton to Balloch the line would have closely duplicated an existing railway, and negotiation led to the latter being made jointly operated, and the L&DR terminated immediately east of Dumbarton, trains continuing on the joint section. Quoted from Wikipedia

Bowling… is a village in West Dunbartonshire, Scotland, with a population of 740 (2015). It lies on the north bank of the Firth of Clyde, between the towns of Clydebank and Dumbarton. It is 1 1⁄2 miles (2.5 kilometres) west of Old Kilpatrick which is at one end of the Antonine Wall and therefore represents the extreme limit of the Roman Empire on the west coast of the island of Great Britain. Quoted from Wikipedia

National Cycle Route 7

… the trail proceeds west along the north of the River Clyde, through Dumbarton to Loch Lomond at Balloch. Quoted from Wikipedia