British Rail Mark 1

British Rail Mark 1 is the family designation for the first standardised designs of railway carriages built by British Railways from 1951 until 1974, now used only for charter services on the main lines or on preserved railways. After nationalisation in 1948 British Railways had kept building to the designs of the Big Four companies, and the Mark 1 was meant as one standard carriage across all lines, much stronger than earlier designs. The design was used for hauled passenger stock, multiple unit carriages and non-passenger vehicles. Developed by Derby Carriage and Wagon Works, they were built at Derby, Doncaster, Eastleigh, Swindon, Wolverton and York. Early vehicles date from 1951 to 1960 and the later Commonwealth stock from 1961, and daily mainline use ended in 2005.