An artillery version of the siege tank was in use by the Confederacy during the Guild Wars.
These tanks were able to be fueled by oil. Mobile siege tanks were in existence by 2480, several years before the official beginning of the Guild Wars. An existing tank design was modified so that it could operate as a conventional tank in addition to being able to deploy the cannon and become a static artillery emplacement at will. However, the conflict demonstrated the need for mobility and as a result an effort was made to make the cannon more mobile.
Prior to the Guild Wars, work had progressed on a static 'final defense' cannon. The dual-mode siege tank concept was a Terran Confederacy response to the flexibility of the goliath.
