A numerical Type describes each model of TARDIS as produced by the Neural Construction Docks. For example the Doctor usually operates a Type 40 TARDIS. Every TARDIS that is grown follows the specifications of its specific "Type."
The Type number is fixed. For example the Doctor's TARDIS is still a Type 40 TARDIS despite the numerous upgrades and modifications it has received over the years. Higher Type numbers indicate later model Time Travel Capsules and, in most cases, later types function more efficiently and reliably then older types. Occasionally, some entirely new feature will be installed. If useful and reliable this feature will be found on all later types and sometimes incorporated into the various upgrades of older types. If a TARDIS Type is particularly successful, then over 300 of that Type might be created.
There were around 100 different types issued before the end of the Last Great Time War. The Type 89 TARDIS is the most advanced non-military TARDIS ever created. Military TARDISes are known to go up to Type 94. This classification system does not include the Space Inter-time Dimensional Robot All-purpose Transport (SIDRAT) constructed by the early Time Lords.
Because later models of TARDIS have larger shift ratios in the wave loops, it's possible to identify the specific Type at a distance by analysing the ratios. A Time Lord can make the same identification by sight, regardless of their disguise, if they check the molecular patina of its exo-shell. They can often tell the general condition of the TARDIS as well. The sound made by the Relative Dimensional Stabilizers during materialization is slightly different for different types of TARDIS.
While many systems can be upgraded to later Marks, some components will forever remain unique to that particular model. For example, when replacing the Main Space Time Element of a TARDIS, the operator should be aware that it must be coded to match the specific Type of that TARDIS. For more details on this see Upgrades and Custom Modifications.
The following color code is used:
- Black: For information from the TV Series, including Dimensions in Time, and 1996 TV Movie.
- Blue: For information from the Novels and Audios including Target, Virgin, BCC, and Big Finish.
- Green: For information from 'licensed' reference sources such as the Technical Manual, Doctor Who Magazine, and the Role Playing Games.
- Red: For information from unofficial sources -The Faction Paradox series, behind the scenes interviews, author's speculation, and popular fan belief.
The TARDIS Technical Index is copyright Will B Swift.