I can't say for every area or how easy it is to do, I can only talk from my own experience. It was impressed apon us quite early how many avenues there are for progression within Network Rail, although it will very much depend on what you are looking for.
I would hazard a guess though that you will not be a Grade 2 after passing the course. Positions are offered now, as I understand it, as a Grade 2 trainee position within a geographical area. During training you will then apply for the actual positions within that geographical area, which could be any Grade depending on the boxes and what positions they require filling.
As for progression beyond that, if you're after the most money then I would assume the highest grade jobs in Scotland would be in Glasgow. More locally if a higher grade box isn't your thing then quite a few Signallers seem to move on to being a Mobile Operations Manager, or a LOM beyond that. The Operations side of NWR very much seems to be your Oyster if you have the desire to progress, however I'm sure many of the more experienced heads in this thread will say that it's not necessarily as simple as it is made out to be.
