It looks what it is, very heavy, solid, and big. I like the use of two tracks of railway.
I have often wondered how useful these rail-mounted guns were. Despite the double track I doubt that it would have been able to fire at more than a small angle sideways (due to the toppling recoil of the discharge). Also, being rail mounted (and on a pair of railways) it was limited in where it could go (although the static Front in WWI would have helped it). Also, being rather conspicuous and slow to relocate, it could have been at risk from aerial bombardment (although the stick-and fabric biplanes probably didn't have heavy enough bombs to upset it much.
Wiki has an interesting article at:
http://en.wikipedia.org/wiki/Railway_gun