Question: The 21 cm Schnelladekanone Länge 45, abbreviated as 21 cm SK L/45 was a German naval gun developed in the years before World War I that armed the armored cruiser SMS Blücher of the Imperial German Navy, during World War I spare guns were converted to railway guns, a railway gun, also called a railroad gun, is a large artillery piece, often surplus naval artillery, mounted on, transported by, and fired from a specially designed railway vehicle, called what?
Sentence (from "10.5 cm SK L/35"): In addition to the Imperial German Navy the 10.5 cm SK L/35 was used by the Royal Netherlands Navy, Ottoman Navy and Spanish Navy.
Relevant evidence: No