Jeremy Corbyn's promise of free bus travel for the under-25s is fully costed. Is war in Syria fully costed? But the meeting of that promise would be only a stage, even if a very important one, in the journey as whole.
Forward to a renationalised rail system as the backbone of a restored public transport network reaching every community all day and all evening, and free at the point of use to everyone. If we can conceive this, then we can achieve it.