Position for 305 mm gun on a railway transporter

Something more mundane: namely, a position for those same TM-3-12 railway transporters, one of which flaunts in the Steam Locomotive Museum in St. Petersburg, and the other flaunts on the memorial site at the Krasnaya Gorka fort. It is a cyclopean slab made of selected concrete with a steel heel for the conveyor. The thickness of the slab is more than 2 m.