The Railways in Britain

In days gone by, the Tory Government, in the midst of selling off lots of things that were publicly owned to the private sector, sold off British Rail.  I would like to think that they did not like the sandwiches, but that would be just too ironic.  The way that it was sold off was unusual, as the rail companies were regionalised, but there was a different company that was responsible for the track and the stations.  I do not think that this is an ideal situation, but it is the situation that we have now.
Today, the new Tory Government have announced that the are going to insist that the private companies invest millions of pounds and turn their trains from polluting diesel to cleaner electricity.  The other advantage with an all electric railway is that costs per mile per passenger are slightly lower. The problem is that where are these companies going to get the money from?  They have already had a cut in the subsidy that they get from the Government into the pot of money that they have.  Out of this shrinking pot they have to find the money to maintain the service that they run, pay their staff to run the railways, then give handsome bonuses to the senior staff for doing such a good job, and pay a dividend to the shareholders, some of whom are our pension funds.
If the railways are having to be 'propped up' by Government subsidy, then surely this is an indication that they were not the sort of industry that would survive in the private sector, or were the terms of the deals they were offered not sufficient for them to make an operating profit.  There must have been something wrong for the subsidy to be still be on offer.  The Labour party are going to have a review of this situation  because, like me, they do not believe that this situation cannot be maintained where shrinking pots of money are being asked to pay for more things.  They have publicly stated that re-nationalisation is not being ruled out, but would not a different sort of structure be better suited to run the service that thousands of people every day rely on to get to work etc?