The Caledonian Railway (CR) was a major Scottish railway company. It was formed in the early 19th century to form a link between English railways and Glasgow. It steadily extended its network and reached Edinburgh and Aberdeen. It also had a dense network of branch lines in the area surrounding Glasgow. It was absorbed by the London, Midland and Scottish Railway in 1923 under the Railways Act 1921. Many of its main routes are still used. The original main line between Carlisle and Glasgow is now part of the West Coast Main Line.