First Great Western can simply add more services without permission from the DfT

MYTH. First Great Western needs express permission from the Department for Transport to add services or to implement major timetabling changes. These have to be signed off by the Department via appropriate derogations. It is, therefore, a patent falsehood for the Department, or anyone else, to claim that First Great Western is responsible for the timetable and services and can make changes as and when it wishes. Of course, none of this is to say that the Department will necessarily stand in the way of FGW adding more services, but it does need to give its express consent. More understandably, permission is also required from Network Rail.