Oh no, why... These fences were not there since this tram line was opened and nobody was injured by a tram until nowadays... I am glad I was there in 2019.)

Until recently, the path was only used by people walking with dogs, tram enthusiasts and junkies. They were therefore responsible for a number of arson attacks. In 2016, the castle still looked like this, but it has become much worse. https://transphoto.org/photo/1071183/?vid=75063
Eventually, the remnants (rather: a ruin with run-down buildings) were sold.
The new owner has made an impressive job of it, also of the adjoining buildings, the gardens and, of course, the castle itself.
He has placed fences around his domain to keep out dissenters.
The path belongs to the estate and only a gateway is missing.
The fact that he has already had this fence installed may not be a coincidence. The path was used by all possible services that work there, on the trees, the verge, the tracks and the catenary.
Not only the trucks of the staff were parked there, but sometimes also a waste container...
As long as the castle was uninhabited, this was not a problem. Now that there is regular passage, I suspect that the owner wants to keep the city services (and those of the tram) outside his domain, so that he can just pass through.
Anyway, that fence has indeed become annoying and it is totally impossible to walk the short distance to the end point.

Thank you for you detailed explatination. I would not expect this area will be in a private possession. It is intersitng he had had this fance installed up to the crossroad (the whole path). Personally, I do not want to say it is little bit selfished but more likely it is...

Just take a look: "Show shooting location on the map" and the map (OpenStreetMap). The path leads to house number 444 and nothing else.
It also has no name and is therefore not a street.
Above it you will find another road, which is actually just as narrow, but has been given a name. This road is also a dead end, but it serves several houses (420 --> 438).
Thus, one can more or less deduce that one street is a public road, while the road next to the tram line is private property.
Such a private road may be used as a service road or included in a walking route, but only with the agreement of the owner. Here I suspect that the new owner has little interest in prying eyes...