 A considerable quantity of exported coal and imported ores, minerals , iron and steel and general traffic is handled at Bowling ...The Railways Act 1921 brought about the "grouping" of the main line railways of Great Britain, and from 1923 the Caledonian Railway was a constituent of the new London Midland and Scottish Railway; the rival NBR was a constituent of the new London and North Eastern Railway, so the competition continued, and the Dumbarton and Balloch Joint Railway was now joint between those two companies.The railways were nationalised in 1948, and the lines in Scotland formed part of the new Scottish Region of British Railways.