I don't think it was the original plan to have all the Western Route controlled from there - by which I mean the plan when it was built - that is why it is only called the Thames Valley Signalling Centre. Then the plan changed and I thought they were planning to extend the building - always a tricky thing when it is a live installation. So I guess they have now realised that and have scaled back their aspirations to match the capacity of the building.
I think there's a difference between what was initially planned - as in going to be done within the foreseeable and plannable future - and what was always intended as the final result. There are maps with the
NR» routes (their management regions, one of which is "Western"), identified one to one with
ROCs▸ (excepting some historical anomalies). But the Western Route Plan of 2013 said:
Signalling migration synopsis
Thames Valley Signalling Centre (TVSC» ) was commissioned in December 2010 as part of the Reading area enhancement programme. The Route has developed a migration plan for the current Great Western Mainline Power Signal Boxes which sees control of the entire line between Paddington and Bristol, Oxford and Newbury move to TVSC by 2015.
That's signalling, but an ROC also holds the ECR (electric power), NR route, and
TOC▸ operations control functions. I suspect that these have ended up employing more people than was foreseen. And of course that "planned" may have assumed that if more space was needed 30 years later than some could be built.
And has someone wearing a "resilience" hat come along to NR's planners of control strategy and asked what the backup arrangements are - e.g. if a major fire puts an ROC out of action for months, how and to where will control of all functions be transferred to be operational the next day? That must be easier to do with more, smaller, control units, though obviously needs some spare capacity somewhere.