INFORMATION:

This is the second type of holdfast in a DFW 55414 emplacement, it also has four pieces of railway line embedded into the concrete this was known as the Pile Mattress and made a more stable platform.
The early emplacements had several ready ammunition lockers around the gun. It was found as the war progressed that the crew needed shelter and more ammunition so this type of emplacement was designed with many ammunition lockers and two crew shelters.