The following list sets out to show all the railway companies set up by Acts of Parliament in the 19th century before 1860. Most of them became constituent parts of the emerging main-line railway companies, often immediately after being built. Some continued as independent companies until the 1923 Grouping; a few retained that independence until 1947. They have been listed under Scottish; and English and Welsh early railways; and under the later main line company which absorbed them. Each of the main line companies after the Grouping has an article listing all companies who became part of, and jointly part of, individual companies. Many of those had been in separate existence since being set up in the 19th century, and were only in 1923 losing that individuality. The list is by no means complete: in 1846 alone there were 272 railways agreed by Act of Parliament, although not all of those were built, since it was the time of the Railway Mania. In addition lines might be extensions to existing ones, but floated as a separate company to separate the risk, and to ring-fence subscriptions, or promoted by a company which was mostly financed by an existing company. An example is the Dore and Chinley Railway which was floated as a company and then adopted and largely financed by the Midland. Scottish early railways Caledonian Railway (incorporated 1845) Caledonian Railway became part of the London, Midland and Scottish Railway on 1 July 1923 under the Railways Act 1921. Aberdeen Railway opened in stages between 1848 and 1853 Brechin and Edzell District Railway Cathcart District Railway Crieff and Comrie Railway authorised 1890 Crieff and Methven Junction Railway opened 1867 Crieff Junction Railway opened 1856 Dunblane, Doune and Callander Railway incorporated in 1846 Dundee and Newtyle Railway opened 1841 (incorporated in Scottish Central Railway) Glasgow and Paisley Joint Railway opened 12 August 1840. Glasgow Central Railway; opened 26 November 1894 Glasgow, Garnkirk and Coatbridge Railway opened 1831 as the Garnkirk and Glasgow Railway Glasgow, Paisley and Greenock Railway opened 29 March 1840; merged with the Caledonian Railway 1847 Hamilton and Strathaven Railway opened 6 August 1860; taken over by the Caledonian Railway 1864 Lanarkshire and Dunbartonshire Railway authorised in 1891 Lochearnhead, St Fillans and Comrie Railway opened Comrie to St Fillans 1 October 1901; opened to Balqhidder 1 May 1905 Perth, Almond Valley & Methven Railway opened 1858 Scottish Central Railway (to