In case anyone things this has anything to do with the current Russia situation, it most likely has not. Stuff like that happens every few years on larger scale and sometimes multiple times a year on smaller scale (e.g. part of Berlin local trains not going because of it). A lot of this sabotage comes from people trying to steal cables, but then also sometimes giving up in the process. Then there a climate crazed peo…
Cables in both Berlin and Dortmund were severed around the same time. This smells of a larger, coordinated oepration.
Getting illegal short term access to the cables around there long runs isn't hard. Like at all.
Finding which cable need to be cut is a bit harder but not too hard either. (It's not a state secret or anything, there are quite a bunch of people which know stuff like that. Worse just by following news in recent years about what interruptions cable theft caused is probably enough to find out where you need to cut cables.) Sure it involves a bit of planing and research etc. But nothing which is beyond what a small handful of misguided but not very stupid people can archive. And in my experience people in the group I mentioned are not stupid at all, misguided sure, but not stupid.