What would really help though is if the rail network was engineered for greater availability and more redundancy, so bits could be taken out for maintenance while allowing a minimum service to continue by re-routing trains, that would provide more flexibility on when to do the work.
That’s what I would prefer. But unfortunately the railways have boxed themselves in to an extent.
First, maintaining diversionary routes costs money. And the railways are always being hammered from all sides on costing taxpayers too much or the high price of tickets. And the wide mix of different stock and the different train companies sometimes makes running diversionary services more complex or impractical. Also diversionary routes generally are significantly slower, due to being a longer distance and or a lower overall line speed. There is often no money or incentive to improve these secondary routes.
Secondly, longer blocks are cheaper and more efficient overall than a series of weekend blocks. But generally speaking train companies and freight companies don’t like longer blocks. So typically, apart from large projects, most engineering work starts late on a Friday night/early hours of a Saturday morning, and continues to the early hours of the following Monday morning. But even this is not as good as it could be, because empty trains have to be able to return to their depots before the lines can close. And move to their start points to form the first services in the morning. This is made worse because some depots are now only just big enough, so you find trains queuing up when entering or exiting… All of these eats into the time that the lines can be closed.
Third, the way that Network Rail has decided to improve staff safety has and is having an impact. The ORR required Network Rail to reduce the risk of staff being hit by trains. Network Rail decided that only allowing staff to work trackside when there are no trains is the solution. But that means engineering and maintenance work (including routine or minor, but still important work) has to be done by closing the lines. If both lines of a double track railway are shut, you can’t use single line working. The staff obviously want better safety, but want better use of technology to protect them rather than having to work lots of nights and weekends which is when normally the lines are shut.
Fourth, the longer you defer work, the more expensive and more time consuming it gets. But to save the current budget, or due to a lack or resources, or lack or access, some work is deferred. But eventually said infrastructure will have to repaired or replaced. And this requires longer blocks.
Fifth, for big projects, the railways are limited by the availability of the contractors. And more importantly, the alignment of different contractors in the same project.
