The Department for Transport and Network Rail plan to improve passenger services on the Great Western Main Line through infrastructure improvements and the introduction of new trains.
The Department for Transport is responsible for funding and sponsoring the programme, while Network Rail is responsible for carrying out infrastructure works to modernise the route.
Electrification of the route between Maidenhead and Cardiff is the largest component of the route modernisation.
National Audit Office report
The National Audit Office (NAO) are shortly due to publish their first report into the Great Western Route Modernisation, though they have previously prepared a Memorandum for the Committee of Public Accounts on the 2014–2019 rail investment programme as a whole.
The NAO's upcoming report will focus on how well the Department and Network Rail planned the programme from the outset, the extent to which previous programme management issues have been addressed, and how the Department and Network Rail are managing the remaining risks to value for money.