The largest element comprises three contracts worth £22m relating to the early stages of resignalling the London – Bristol Great Western Main Line in preparation for the main works between 2013 and 2015. The project also involves preparations to electrify the line and to overlay ERTMS.

Another contract worth £12m is to renew the signalling on a 29km section between Horsham and Arundel. This includes installation of the latest version of Smartlock 400 interlockings to replace Signalling Solutions's pilot version. The system will be commissioned in October 2013.