I’m also intrigued how they will resource this timetable improvement as they seem to struggle even with the reduced timetable.
There's a few factors at play.
Firstly, sometimes a reduction in service doesn't actually reduce the amount of staff required. The TfW timetable was already pretty well optimised to use limited resources in the best possible way - reducing the service levels actually made it less efficient as staff weren't necessarily in the right place to work their next train as the train they needed to get there was no longer running.
In the Covid timetable, one of the jobs at our depot featured five hours of shunting units at a major station. Normally those units would ruin though, but during Covid they were terminating and needed shunting. Now those 5 hours are spent working one of the reinstated round trips instead.
Also, some of the longer breaks in our jobs whilst we waited for a train to work back have been shortened; again, much more efficient.
Finally, it's no longer the summer holidays, so there are much fewer staff on annual leave than a few weeks ago.