George Stephenson locomotive, and was probably built at Killingworth Colliery workshops around 1815–1820. The twentieth century In 1900 the North Eastern Railway started replacing the gas lighting in the station with electric arc equipment. Further use of electricity came from 1904 when several suburban lines were electrified using the third rail system, to form the Tyneside Electrics system, electric trains were introduced, using Central Station from 1 July 1904. The tracks on platforms 1 to 6 were equipped with electrified third rails, and platform 7 was later electrified to handle electric trains to . Another major development came on 1 October 1906 when the King Edward VII Bridge was opened, crossing the Tyne to the south-west of the station: Since 1850 East Coast Main Line trains had entered Newcastle from the south via the High Level Bridge to the south-east, this meant however that they had to reverse in order to continue their journey, which lengthened journey times and led to congestion at the busy junction east of the station. The four-track King Edward Bridge remedied this by allowing north–south trains to leave or enter from either side of the station. The triangular junction at the Gateshead side also allowed for greater flexibility, allowing trains from to use the new bridge if necessary. In 1909, Central station became Newcastle's only major city-centre station when the former Blyth and Tyne Railway's terminus at was closed, and its trains diverted to Central station via a new connection to station. Metro station The Tyne and Wear Metro system opened in 1980, taking over and improving many of the Tyneside suburban routes that had declined under British Railways management. The underground Central Station for Metro trains was constructed during the late 1970s underneath the main line station, and opened in 1981. Part of the porte-cochère was temporarily dismantled while excavation work took place. The Metro system was a considerable success; Many conventional rail services were transferred there, and several of the east end bays were closed and converted to car parking and other usage. The Carlisle line was diverted to enter Newcastle over the King Edward Bridge of 1906, and a large out-of-town shopping development, the Metro Centre, was opened with a station on that line. The changing pattern of railway services meant that terminating trains were significantly fewer and through trains had increased. The emphasis on bay platforms at the station was no