Yeah. I went adventuring with NeroDK and found the railroad. We just thought it was like a work in progress thing.. or maybe it's something else...? Rainbow illuminati confirmed?
Not so sure, but I did zoom in on the photo. There is a sign on the "thing" (I think) and there are some bloodstains. Not so sure what it is still, but maybe these are clues for suggestions on what it really is for others.
It's a template for a continuation of the railroad that ends before the barrier. That whole icy area plus some of the mountains are blocked off until finished, so anything weird seen beyond the barriers will be removed before the map is updated for the public to use.