The whole purpose of GBR is to join up the railway, which reduces the interfaces and transactions, and that means fewer people.
What the press have is what has been released internally in two parts of NR; every other part has had a very similar communication to those who might be affected. Whilst I don’t know, it’s almost certain that NR has not briefed the press, because that sort of briefing would be done by the national media team (“a Network Rail spokesperson”), and not the two senior directors quoted. It looks like someone affected has gone to the press with the internal comms. Hence why it has “been seen by The Telegraph”, which is press language for someone sending something in whatever is the digital version of a brown envelope.
The article is in any event misleading. It is not 15% of the workforce, as is patently obvious from the numbers the article quotes, namely “estimated” (by who?) 2,000 posts out of 41,000. That’s less than 5%. Maths evidently not this reporter’s long suit.
The proposal is, AIUI, to reduce the budgeted management cost by 15%. It only directly affects managers, and will affect higher graded posts more (as that reduces cost more per post). Personally I’d be surprised if 2,000 people end up leaving, as there’s quite a few vacancies being carried in some places.