Saw this years ago (before there was a place here where it wouldn't be offtopic), just found it this morning again:
As the description says, "model train without model railroad"
And lest you think he only runs "train set" consists up there:
Here's a cab ride that illustrates just how minimalistic the suspended trackage really is. According to the owner's answer to a comment in the video below, it's 4mm stainless steel circular rod, attached to plexiglass "ties" with superglue. He bent the curves himself using a plate roller:
By the way, the layout owner resides in Norway. One can only imagine how much extra expense was incurred importing the consist of this particular train (although we all know he likely did it a little at a time):
There is only one other video on this particular channel. Since the newest video was posted four years ago, it's anyone's guess as to whether this layout still exists.