Mark I Travel Machine

The Mark I was the name given by Davros to a Travel Machine prototype, the casing of the first Dalek that he created. It was an experimental life support unit modeled after his own chair. Besides the transplanted Thal brain, it included a life support matrix, an optical stalk, feeding tubes and was activated by a power conduit with only 92% distribution. (AUDIO: Guilt)

The Daleks were later perfected by Davros in the Mark III Travel Machine. (TV: Genesis of the Daleks)

Other accounts stated that large groups of Daleks matching the descriptions of the Mark I Travel Machine were created after a devastating neutronic war forced the Daleks' "forefathers" into casings after horribly mutating. (TV: The Daleks, COMIC: Genesis of Evil) A Black Dalek later told Davros that it had been created by the neutron war with Davros merely accelerating the Daleks' evolution, giving both accounts the scope to be accurate. (PROSE: War of the Daleks)

Mark I Travel Machines were physically distinguishable from later Dalek models by their lack of slats.

History
The first Mark I Travel Machine created by Davros hosted the brain of Baran, a captured Thal spy. (AUDIO: Guilt)

A group of Mark I Daleks were stranded in their city on Skaro, as their casings were powered by static electricity channeled by the metal floors of the City, preventing them from leaving it. While they were in the city, the Daleks monitored the radiation count as it continued to drop. They had ambitions to leave the city and rebuild their planet. They eventually found that the Thals had also survived what was known as the neutronic war. After discovering that they had become dependent on the background radiation to the point of the anti-radiation meds Susan Foreman gave them being lethal to them, the Daleks attempted to vent radiation from their nuclear reactors into the atmosphere which would have left them as the only living species on Skaro. The First Doctor and his companions led a Thal assault and deactivated their power, believing that he had wiped out the Daleks altogether in the process (the necessity of which crime he lamented, though he saw no other way). (TV: The Daleks)

Mark I Travel Machines were among the Daleks who operated on the rebuilt Skaro where the dying Davros lived as he called the Twelfth Doctor to him. (TV: The Magician's Apprentice) These Daleks were destroyed by the rejuvenated Daleks from the sewers. (TV: The Witch’s Familiar)

Behind the Scenes

 * "Mk I Dalek" is the fan name given to the first model of Dalek casings (TV: The Daleks, COMIC: Genesis of Evil) which reappered on the reconstructed Skaro near a dying Davros (TV: The Magician's Apprentice) and are distinguishable by their lack of slats. The "Mk II" designates the one with a dish from The Dalek Invasion of Earth and "Mk III" --matching the designation from Genesis of the Daleks-- is for the one with slats first seen in The Chase.