u/Epicllama266

I remember seeing a post on here but I can't find it again!! I'll describe it:

It was an amazing picture of a giant seawall guarded by armoured trains with enormous cannons on them. It was from a novel about a world where caterpillar tank treads were never invented so armoured trains were more viable. The comments complimented the art but criticised the mobility of the cannons and how the recoil from them would be a problem.

Csn anyone help me find this? Thanks!!