Enn'llien SteamTank (EGA Siege tower) miniature for RPG

In a Pathfinder RPG campain, i'm playing a Half-elf Gunsligner/gunsmith and inventor named Enn'll Nothridge who's life work is to create a serie of steam powered medieval mobile artillerie ( in other words, tanks) which are named after him.

This one is STUPID, (TLDR after this paragraph..) Basically i thought siege towers were created in a town and moved to the battlefield, but i was wrong, seige towers are made on site and are abandoned after, they are disposable... so my idea of saving ti