The vast bulk of staff who would be made redundant would be things like delay attribution clerks, who are responsible for funnelling large volumes of money out of the railways and into the pockets of private corporations.
I know that it has been said before but let's be clear that delay attribution is a concept that was actually begun by BR, once the majority of train running data was capable of being captured automatically. The TRUST system, which underpins attribution was developed by BR.
Previously performance investigation and management relied on trying to piece together what had happened by wading through control logs, train registers, guards' journals, station supervisors' tick sheets, etc. This process kept many Area Operations Clerks and others busy on day shifts, sending out 'please explain' memos after the event. Frankly this 'process' was spectacularly ineffective and I speak from a position of having participated in it over many years.
Like the human body the railway is a complex system. Just as staff in a hospital are regularly capturing data about temperature, blood pressure, heart rate and so forth in order to manage recovery, so data on train operations is now captured continuously.
Another analogy is with fault finding in electrical systems. If there is a power cut the network operator will check for faults in its own equipment, send out response staff, check to see if outside influences such as weather or vandalism have been experienced and so forth. If no problem is established from this checking (equivalent to the Network Rail 'side' of attribution) then the customer's equipment connected to the network has to be checked (equivalent to the operator's role in attribution). Most of the time these processes will be carried out without dispute.
With genuine information on exactly what has been going wrong both sides of the industry can target and prioritise actions to prevent recurrence or improve mitigation.
This essential activity is only slightly related to the separate operation of the performance regimes. These only require to know the share/proportion of responsibility (Network Rail, operator on self or other operator), not the root cause, which is the focus of delay attribution.
The idea that a nationalised or 'integrated' industry would then stop delay attribution, after we have benefitted from it for over 20 years, is ridiculous.