This is an entirely government-led problem. There is nothing GTR nor Network Rail can do in terms of implementing policy without government sign-off. The principle issue of this latest cock-up is about the lack of trained drivers - they don't exist. Even the rail companies themselves highlighted...
ABC has been campaigning for the past three years, even bringing a (partly) successful court case against the Department for Transport. They are also campaigning for full access for all passengers, rather than the policy of not allowing disabled passengers on if it will make the train late, or...