Vortex drillers were a type of vortex ship that were used in the early days of Gallifrey to tunnel through the Time Vortex. This was stopped, however, due to the damage this caused to temporality.
Vortex drillers resembled castles with drills for turrets and held altars for Gallifreyan cults, along with corridors to time that could drive people mad if they stared into them. They possessed mineralic circuitry and controls responded to thoughts. Compared to a TARDIS, the Tremas Master considered the potential of a driller to "leap" across the universe a greater method of travel.
The Master used a vortex driller to attempt to find the First Consciousness of the Nestenes, which attempted to merge with the ship to gain access to time, before the Fifth Doctor trapped it using a makeshift Time Scoop. Kamelion programmed the ship to land on an empty planet. (AUDIO: The Auton Infinity)
In the Warrior's universe, vortex drillers were used in the Time War. (AUDIO: The Key To Key To Time)