It had me puzzled until I read the whole article. Without explanation, I would say that it's a montage :D (at first glance, I didn't even notice the vertical rail peeping out), it's good to learn something new today, thanks for sharing.
p.s. your catchy "title" is really intriguing :)
It was about time that I contributed something unique to #photocircle :)
I was pleasantly surprised by it, thanks :) it had me thinking also on how you write your post, the way you shot this scene and also the technical info you put into it is something of high value. Im also on the engineering / construction side & with photography as my hobby, so i have a lot of take away from your post. Cheers!