While new
EMUs▸ for Thames Valley from the outset had been looked at before, the following is from the Network Rail
CP5▸ plans dated 31st March 2014:
DfT» have indicated that the initial EMU operations will utilise class 319 units operating up to 12-car in length over the following core route sections:
Core routes
Paddington to Oxford.
Slough to Windsor and Eton Central.
Maidenhead to Marlow.
Twyford to Henley.
Reading to Newbury.
Reading to Basingstoke.
Diversionary routes
Acton East to North Pole junction.
Reading West Curve.
Diversionary routes
Acton East to North Pole junction.
Reading West Curve.
Ancillary movements
To and from Reading Train Care Depot
They do, however, mention potential future work to allow new EMUs capable of 110mph operation.