Spending money on new trains would be a massive start. Longer trains would increase capacity immediately. Shaving a few minutes off a journey between Birmingham and London is nowt. Investment in the infrastructure is what is needed along with trains fit for purpose. Not cramming people in like sardines.If we want a railway to be proud of then that means investing in high speed lines. Should have done it 30 years ago but better late than never.
Spending the money just on new trains might make the journeys more comfortable but doesn't increase capacity at all.