It's not just money, but how it's spent. They could, for example, spend less in the South to help benefit the North.....
They could, however if you wanted the best outcome for rail you'd need to spend more everywhere so that the expectation was that travel choices would be:
Walk
Cycle
Public transport
Shared access cars (taxi, car clubs, car hire)
Personal car ownership
The problem is too many start with personal car ownership.
For that to reverse there's a need to change the perceptions of people.
I was reading an article about a couple who live in the boundary of the ULEZ in London and own at least 3 vehicles and they were complaining that to turn one way out of their driveway meant costing them £12.50 when done in older vehicles.
Many would think that is outrageous and how dare the government do this to them. However that just highlights how skewed our thinking has got. They live in a city with some of the best public transport in the country (and probably fairly good in works standards too) and yet too many would feel sympathy (no reference to a need for health reasons and whilst reference is made to a van, implying work, and parking at a office - no mention of "needing" vehicles for work, as if that's so obvious that it's not worth saying overtly).
The better user of money could be argued that rather than paying an average of over £3,000/year on all the costs of car ownership it would likely be better if we paid a little more in taxes (say an average of £500, which would generate £16bn/year if applied to income tax payers) and then only had an average outgoing of £2,000 rather than £3,000 (i.e. still enough to own one car within a couple, if really needed).
That would be enough to build a basic metro system in 8 major cities each year (based on the announcement that Leeds' system would cost that much).
Obviously it would take a few years to deliver fully each, so there'll still be funding available for heavy rail and buses whilst developing the metro systems.
Overall we could be paying less overall (even though we'd be paying more taxes), the problem is that we've got the mindset that we should pay less taxes, even if it means paint for stuff that should be provided by the state. However in doing a chances are we end up paying more for those services as there's inefficiencies in the payment systems (it's cheaper for me to pay £100 once than £5 each time I do something and I do it 20 times, as there's a staff cost with each payment).
This is why paying for stuff to cover Central government cuts are always going to lead to lower quality of service.