Among the rarest and most fearsome war-machines of the Empire of Man are the Steam Tanks, and upon each of these iron behemoths is mounted the mighty Steam Tank Cannon. Unlike the black-powder guns of the artillery train, this cannon draws upon the same seething boiler that drives the tank forward, harnessing pressurised steam to hurl its shot with tremendous force and unnerving speed.
The Steam Tanks were the work of Leonardo da Miragliano, the greatest engineer the Empire has ever known, and the secret of their construction died with him. Only a handful still function, each a priceless relic tended by devoted engineers who coax and curse their ancient mechanisms into life. The cannon they carry can be fired again and again without the laborious reloading of a conventional gun, so long as the boiler holds its pressure, raining destruction upon the foe from within a fortress of riveted steel.
To see a Steam Tank grind forward through the smoke, its cannon booming and its hull impervious to blade and bolt, is to witness a legend of the Empire made manifest. Enemy warriors hurl themselves against its armoured flanks in vain, and the greenskins and beastmen who despise all things wrought by clever hands flee before it. For all its temperamental nature and the constant fear that its boiler might one day burst, the Steam Tank Cannon remains a symbol of Imperial ingenuity at its most triumphant.