What if it's caused by random reboots lasting up to 1h? :)
Of course I'm half joking, but I wouldn't be surprised if software problems contributed to the delays (which tend to chain, as trains need to wait for each other, etc).
Curiously, I was riding a TGV in France few weeks ago, and due to some track problems, we had to change the direction and go back to previous station (and then use different track to go forward again).
It took more than 1h to start going back, and I wonder how much of it was making sure the track is clear, and how much was "rebooting the train" or whatever else was necessary.
I'm guessing that these days anything might need to be rebooted, including track themselves (I mean: there are misc detectors there).. Sometimes I'm in awe how strong the overarching duct tape is :)
Of course I'm half joking, but I wouldn't be surprised if software problems contributed to the delays (which tend to chain, as trains need to wait for each other, etc).