It is nothing new, it goes back to BR days, one of the issues now is the fact that there are more and more trains running, the time for getting access to the line, is getting shorter and shorter, but the work still has to be done, thus they work right up to the wire, it is not unusual here for a possession to be given up at 0440, just 5 mins before the first train, in reality this is too late for the Signaller, who has to remove, or may have to remove hundreds of reminders on the panel / workstation, the possession will have been given after the last passenger train at 0215, gives them a mere 2 hours or so to get the work done, there is just no time to take all of the stuff off track, sometimes it is fortunate to have materials left trackside, if there is a fault that crops up, that needs a bit of rail cut in, or some ballast or clips replacing, there are materials at hand, or at least fairly close by, and yes there are also 'track clearance' possessions, but not as many as track repair ones !
A few months ago we had a defective rail, needed a 20MPH ESR, luckily there was a good bit of rail about a mile away, and this was taken to site during the day, ready for them to get stuck in that night a put the new bit in, the 20MPH was removed the next morning, had this bit of 'scrap' not been handy, it could well have been over a week, or a lot longer, before they could get some new rail to site.