Doncaster PSB

Doncaster PSB (Power Signal Box) is a signalling centre on the East Coast Main Line (ECML) railway in the United Kingdom, principally covering the line from London to Edinburgh but also encompassing other lines diverging and converging to the ECML. The signal box celebrated its 25th birthday in 2006.

On Sunday 8 July 1979, the first section of the control panel in the new signal box at Doncaster became operational, controlling the movement of all trains in the immediate area of Doncaster station. Not only was this a significant landmark in the progress of the whole resignalling and track rationalisation project, but it also represented a further major step forward in British Rail's drive towards the complete modernisation of the London - Edinburgh East Coast Main Line. The signal box was completed in 1981 and was officially opened on 8 December 1981.

The Doncaster installation was the third major signal box to be commissioned on the East Coast Main Line, the previous two being King's Cross, completed in 1977 and Peterborough in 1973. Before the scheme's authorisation in 1974, train movement was controlled by a mixture of outdated semaphore and colour light signals operated from 52 signal boxes mainly containing mechanical lever frames, many dating from the 19th century.

Power signalling, however, was installed in two signal boxes, one at the north and the other at the south of Doncaster station. The work was planned and some equipment was on site before the Second World War but the installation was not commissioned until 1949. Searchlight colour light signals and electric point machines were controlled from switch panels. The interlocking equipment was unique being a sequence switch interlocking system manufactured by Standard Telephone Company using telephone switching techniques to the technical specification of the signal engineer of the then Southern Area of the London and North Eastern Railway. The sequence switches consisted of a rotary contact shaft which was rotated to a route position and proved a circuit through contact wipers. Each switch had a "home" position and eleven route positions. When a route was initiated, a clutch was engaged on the appropriate switch to rotate it into its correct position thus setting up the appropriate interlocking circuits through other switches and relays. The installations proved to be remarkably reliable, serving a very useful purpose but were eventually life expired.

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