Locomotives of the Stockton and Darlington Railway
The Stockton and Darlington Railway (S&DR) was a railway company that operated in north-east England from 1825 to 1863. The world's first public railway to use steam locomotives, its first line connected collieries near Shildon with Stockton-on-Tees and Darlington, and was officially opened on 27 September 1825. The movement of coal to ships rapidly became a lucrative business, and the line was soon extended to a new port and town at Middlesbrough. While coal waggons were hauled by steam locomotives from the start, passengers were carried in coaches drawn  by horses until carriages hauled by steam locomotives were introduced in 1833. The S&DR was involved in the building of the East Coast Main Line between York and Darlington, but its main expansion was at Middlesbrough Docks and west into Weardale and east to Redcar. It suffered severe financial difficulties at the end of the 1840s and was nearly taken over by the York, Newcastle and Berwick Railway, before the discovery of iron ore in Cleveland and the subsequent increase in revenue meant it could pay its debts. At the beginning of the 1860s it took over railways that had  crossed the Pennines to join the West Coast Main Line at and Clifton, near . The company was taken over by the North Eastern Railway in 1863, transferring of line and about 160 locomotives, but continued to operate independently as the Darlington Section until 1876. The opening of the S&DR was seen as proof of the effectiveness of steam railways and its anniversary was celebrated in 1875, 1925 and 1975. Much of the original route is now served by the Tees Valley Line, operated by Northern. Locomotives were sometimes renumbered, and the old numbers re-used for new locomotives. The following  list does not include all renumberings. Disposal. When the North Eastern Railway (NER) took over the Stockton and Darlington Railway (SDR) in 1863, the SDR stock included 157 locomotives. The SDR locomotives were administered by a separate committee until 1873. The SDR locomotives were renumbered in 1873, mostly by the addition of 1000. In September 1875 there were still 55 SDR locomotives in existence.