Last update 1 December 2020
Please select a starting letter from the links below:
| Code | Signal Box | Note | ELR | Mileage | Opened | Closed | Control to |
|---|
| U | Uddingston Junction | WCM2 | 93m 44ch | 27 June 1937 | 18 September 1973 | Motherwell (M) | |
| UN | Uffington | PMJ | 12m 74ch | 26 June 1909 | |||
| U | Uffington | MLN1 | 66m 42ch | 1897 | 3 March 1968 | Swindon (SN) | |
| UF | |||||||
| DM | Down main line automatic signals | ||||||
| UM | Up main line automatic signals | ||||||
| UC | Ufton Crossing | BHL | 43m 39ch | 14 February 1943 | 3 December 1977 | Reading (R) | |
| UJ | Ulceby Junction | Formerly named Ulceby South Junction | BRI1 | 100m 32ch | 1910 | 30 December 2015 | York Rail Operating Centre (CB/MB) |
| UY | Code used with semaphore signals | ||||||
| D | Down line automatic signals | ||||||
| U | Up line automatic signals | ||||||
| Ulceby South Junction | See Ulceby Junction | ||||||
| UN | Ulverston | Code used from 2008 | CBC1 | 19m 47ch | 16 December 1900 | ||
| UC | United Colliery | WSJ2 | 203m 56ch | 9 August 1970 | 1 October 1974 | ultimately Chester PSB (CR) | |
| UCR | Distant signals | ||||||
| UC | Unstone Colliery Sidings | TJC1 | 149m 68ch | 15 January 1972 | Dore (D) | ||
| Uphill Junction | MLN1 | 138m 6ch | 1884 | 29 January 1972 | Bristol (B) | ||
| UM | Upminster | FSS2 | 15m 38ch | 17 April 1995 | Upminster [new] (UR) | ||
| D | Down line automatic signals | ||||||
| U | Up line automatic signals | ||||||
| UR | Upminster [new] | FSS2 | 15m 38ch | 11 September 1994 | 6 December 2019 (planned) | Romford Rail Operating Centre (UR) (planned) | |
| NL | North London Line signals. Code used from 4 January 2011 | ||||||
| UGF | Ground frame controlled signals | ||||||
| UE | Upminster East | FSS2 UPG | 15m 44ch 0m 5ch | ? | ≈1995 | Upminster [new] (UR) | |
| UW | Upminster West | FSS2 | 15m 15ch | ? | 6 February 1961 | Upminster (UM) | |
| UY | Upney | FSS2 | 8m 9ch | 27 March 1961 | Barking (BK) | ||
| M | Upper Abbey Mills Junction | FSS1 | 3m 61ch | 1 May 1961 | Fenchurch Street (F) | ||
| UH | Upper Holloway | TAH1 | 2m 76ch | 10 November 1985 | |||
| CCH | Upper Warlingham | SCU1 | 15m 30ch | 10 March 1884 | 2 November 1985 | Three Bridges [new] (T) and Oxted (OD) | |
| U | Upton Park | FSS1 | 5m 37ch | 1 May 1961 | Barking (BK) | ||
| UN | Urlay Nook | Downgraded to gate box 25 November 2013: line controlled by Bowesfield (B) | DSN1 | 7m 38ch | 1896 | 11 March 2019 | York Rail Operating Centre (B) |
| R | Distant signals | ||||||
| US | Usan | Code used from 2002 | ECN4 | 28m 48ch | 6 May 1906 | 2 February 2010 delayed from 28 January 2008 | Montrose North (MN) |
| UH | Usworth | Code used from 24 April 1982 | FEP | 17m 45ch | 1898 | 1991 | |
| U | Uttoxeter | Two signals only. Last all-new mechanical 'box | NSS | 16m 0ch | 28 January 1981 | ||
| UR | Code used from 2 January 2008 | ||||||