Late 1980s: BR Operational Research, Derby, modelled the track layout for British Airways' proposed high speed rail link from Paddington to Heathrow. Concept translated into design by BR's civil engineering design group in Swindon with help from HM Railways Inspectorate. BR CEDG was taken over by Scott Wilson in 1996.
Early 1990s: HEX track modified by BR Great Western Region, Reading, by 1993. Contractor Amey took over this division at privatisation. Signal design altered by BR Signal Projects Office in Reading, later taken over by Adtranz. New signalling contract won by Westinghouse in 1992. HMRI worked closely with the project which was commissioned from December 1992 to August 1993.
2 August 1993: Poor visibility of signal SN109 at Ladbroke Grove highlighted after it was passed at red. The Signal Sighting Committee asked that the red aspect be moved to the left away from the other lights.
Oct 1994: SN109 layout altered.
1996: Atkins Rail, Scott Wilson and Beard Dove joined Railtrack project delivery team to install HEX electrification. System switched on in May 1997, HEX service began on remodelled track in mid-1997.
19 Sept 1997: Seven people died and 150 were injured when a Great Western intercity express passed a red signal and hit a freight train at Southall.
27 November 1997: Railtrack submits its completion certificate for the Paddington remodelling to HMRI. Formal approval was withheld until after the Southall crash inquiry. HMRI highlights a shortage of inspectors to cope with growth in railway work.
4 February 1998: 'Near miss' reported between two trains after SN109 was overshot.
15 Jan1999: Railtrack, HMRI, Great Western, Thames Trains and Amey set up working group to investigate multiple SPADs in the Paddington area. Michael Hamlyn Associates outlined options for SN109 in March 1999. Flashing yellow aspect removed from SN109 by 31 January 1999 and approved by HMRI.
5 October 1999: Ladbroke Grove crash. Thirty people killed and 245 injured when a Thames Trains train passed SN109 at red and crashed into a Great Western intercity. HSE investigation assisted by WS Atkins and AEA Rail.
8 October 1999: HMRI published its interim report stating that the investigation will focus on 'system failure'. HMRI issues a prohibition notice preventing the use of SN109 until modified. Railtrack immediately appealed.
17 October 1999: Former BR senior manager Roy Bell criticised the Paddington layout.
21 October 1999: Reduced service into Paddington restarted without the fatal line and with many signals out of service.