Keep going and going and going. There are a lot of trains (of course) but once you get past that there are a lot of very interesting photos, especially the shows that look extravagent and unique. This guy documents his trips well!
Hope it is backed up well (guess on the archive sites).
To save anyone else the hassle, this is where he finally crosses into NK:
https://vienna-pyongyang.blogspot.com/2008/09/tumangan-north...