The main thing I am noting here is that this fire has been without death or injury (I stand to be corrected) which is a good thing.
The way building legislation works in the UK is that it is reactive meaning that, as long as it's built right, the newer the building the safer it is in a fire although the priority is safety of people in it rather than the building itself. Being the age it is, this building will predate compartmentalization which stops the spread and seems to have, in a fortune accident of design, protected the station accordingly.
It will take a long time for the building to be rebuilt as whenever insurers are involved it takes time so the people of Glasgow can expect hoardings for a long time to come.
Well done to the fire brigade and railway staff involved