Interlockings
The interlockings controlled by Swindon Panel have a standard circuitry design known as BR(WR) E10k, derived from the reference number of the series of drawings describing this design (E10000 series). It is a freewired interlocking design (Western Region never used geographical interlockings). The term 'freewired' means that all of the interlocking is bespoke to its particular location, consisting of individual relays wired together to suit that particular application. By contrast, a geographical interlocking consists of pre-wired generic packs of relays which are combined together like building blocks to build up the interlocking. Geographical interlockings are quicker to install and require less on-site testing but as not all of the available functions in each relay pack may be required there can be considerable redundancy. The wasted expenditure of this redundancy and the higher initial cost of pre-packaged units has to be balanced against the savings in installation and testing costs. Western Region decided that, in their opinion, freewired interlockings provided better value for money.
The first E10k interlocking was installed at West Ealing in 1955. The panel at West Ealing was supplied by MV-GRS to their standard NX Turn-Push design and the E10k interlocking system was influenced by MV-GRS interlocking practice.
The table below shows the interlockings in the Swindon Panel area:
| Interlocking | Site Code | Type | Commissioned | De-commissioned |
|---|---|---|---|---|
| Uffington | S.277 | BR(WR) E10k Freewired | 30 May 1965[1] | Extant |
| Bourton | S.280 | BR(WR) E10k Freewired | 01 October 1977[1] | Extant |
| South Marston | S.282 | BR(WR) E10k Freewired | 11 June 2000[1] | Extant |
| Highworth | S.283 | BR(WR) E10k Freewired | 03 March 1968[1] | Extant |
| Swindon | S.296 | BR(WR) E10k Freewired | 03 March 1968[1] | Extant |
| Wootton Bassett East | S.306 | BR(WR) E10k Freewired | 23 March 1968[1] | Extant |
| Chippenham | S.318 | BR(WR) E10k Freewired | 23 March 1968[1] | Extant |
| Thingley Jcn | BR(WR) E10k Freewired | 23 March 1968[1] | 11 February 1975 | |
| Thingley | S.320 | BR(WR) E10k Freewired | 11 February 1975[1] | Extant |
| Wootton Bassett West | S.308 | BR(WR) E10k Freewired | ca. early 1980[1] | Extant |
| Hullavington | S.313 | BR(WR) E10k Freewired | 23 March 1968[1] | Extant |
| Kemble | S.332 | BR(WR) E10k Freewired | 27 July 1968[2] | Extant |
The Uffington interlocking was commissioned before Swindon Panel came into existence as it was originally controlled by Uffington signal box. It migrated to control by Swindon Panel on 3 March 1968.
The Swindon interlocking is located at the signal box with the panel and is controlled directly. All the other interlockings are sited at their geographical locations, remote from Swindon Panel, and are controlled through remote control systems.
Related Documents
References
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