In 2015 the GB Government Public Accounts Committee reviewed Network Rail's 2014-19 investment programme, and in particular the programme of enhancements works on the Western Route (The Greater West programme), and concluded that cost increases on the programme were “staggering and unacceptable”; the programme had not integrated all the elements needed to deliver benefits for passengers; and the infrastructure enhancements and new trains procurement were seen as two linked projects, rather than “one programme which needed to be managed as a whole”.

By January 2018 the TGW programme had successfully brought into passenger service the first of the new class of Intercity Express Trains and over 40 Class 387 Electric Multiple Units on the Western Route resulting in significant additional seat capacity in the London Thames Valley Area and significant additional seat capacity further west as Class 16x stock was cascaded to Bristol and beyond. This paper presents a case study on how, since the 2015 Public Accounts Committee, the Greater West Programme has been managed at a cross-industry, `whole-system' level and how system engineering and project/programme management processes were combined into an innovative approach by the Industry Systems Integration team to deliver the whole system outcomes