This is just political jockeying one side against the other no matter who is in power.
This is down to Network Rail, but major maintenance need to be undertaken. Years ago in time of British Rail or even British Railways maintenance even then needed to be undertaken, so did they close various sections of the railway or allow railway workers to work while trains were still running.
If it was the latter then now this would, most likely, not be allowed due to Health and Safety, as workers could be killed or seriously injured in that process.
Maintenance needs to be done to ensure the continuity of the system and maintain a degree of quality while respecting safety of the workforce.
There may be other ways, but when privatisation was brought in most of the British Rail system was extremely antiquated due to lack of serious investment during the history of the UK Railway.
Now we see many improvements in mainline stations and rolling stock, while the staffing has been cut back, sometimes due to improvements in technology, signaling for one.
But our railways still have a long way to go before we can see the remotest substantial and sustainable improvements. This requires major investment and extensive maintenance work and some delays and reductions in service will be required, unless there is automated.
Then that will lead to more reductions in staff, creating more strikes and more chaos for the persons relying on the rail system for work and also pleasure.
It is impossible for all to have everything, but it should always be to the minimum of disruption over the shortest period, but that requires even more investment.
The ‘merry-go-round’ is never-ending.