Apologises, if this has been mentioned previously in the thread, but if bringing everything back in house means that you are bringing not only passengers services, but freight services too back under state control, then you are likely to see more lorries back on the road with that I suspect, then you are currently seeing with less lorries being on the road with private companies having more ability and spending power to be obtaining more in the way of needed locomotives and trailers etc... for carrying goods.
Yes, you have Direct Rail services which is a publicly owned company that has class 57, 66, 68 and 88 within it's fleet. But you also have Rail Operations Group, which if I am not wrong is a privately funded company which has class 37 locomotives in it's fleet but will soon also be having 30 class 93 bi-mode locomotives, plus class 768 bi-mode multiple units and class 319 dual voltage units. There is also GB Railfreight which has many locomotives in it's fleet, with the class 99 joining the fleet from 2025. Not forgetting DB Cargo, Colas Rail and Freighliner all of which I believe are privately owned?
I can see passenger services being brought under public control, but I cannot see freight going the same way as it needs to be the freight businesses themselves making the changes or being pushed to make those changes by their customers whose goods are being delivered. That would not be able to happen, if freight companies are publicly owned.