These WWII trains were mounted with giant cannons but there was one problem—they needed a circular track to aim. See the creations on Combat Trains: https://bitly.com/3iEHLNc | Smithsonian Channel Aviation Nation

Explosive Coal - The Secret Weapon Hidden in Coal, How Spies Sabotaged Germany in the Second World War. During the darkest days of the Second World War, Allied intelligence turned one of Germany’s most vital resources into a deadly weapon. Coal powered Nazi trains, factories, power stations, and steelworks. But hidden among ordinary fuel supplies were explosive coal bombs — carefully disguised charges designed to look exactly like real lumps of coal. Once shoveled into a boiler, the result was c