The Doctor's TARDIS

The Doctor's TARDIS, frequently called simply "the TARDIS" — often called "the Ship" by the First Doctor — was an obsolete Type 40 and/or Mark I TARDIS used by the Doctor as his primary means of transport. Capable, like all TARDISes, of travelling through space and time, the Doctor travelled in his vessel from the beginning of the universe itself shortly after the Big Bang (DW: Terminus, Castrovalva, BBCR: Slipback) to the death of the universe in year one hundred trillion, when all stars evaporated. (DW: Utopia)

Procurement
In his first incarnation, the Doctor implied that he had built his TARDIS himself. (DW: The Chase) However, many other accounts indirectly implied or directly insisted that he had, in fact, stolen it, although he had intended to give it back. (DW: The War Games, Planet of the Dead, The Big Bang, The Doctor's Wife) One account claimed that he had stolen the TARDIS from the Time Lord Marnal (EDA: The Gallifrey Chronicles) whilst others implied he had stolen it from the general, government-controlled "stockpile" of TARDISes, after the model had been officially decommissioned. (DW: The Deadly Assassin, ST: The Exiles)

None of these accounts precluded the possibility that he had somehow been responsible for its creation, however. Indeed, another account found compromise between theft and creation, claiming that while the Doctor had not completely built the TARDIS, he had substantially modified/rebuilt it. The net effect of his tinkering, according to this view, was that he achieved control of the TARDIS without having a mental link with it. This allowed him to bypass the feature on most TARDISes which sent a tracking signal to the Time Lords. (EDA: The Taking of Planet 5)

This notion of the Doctor bypassing a mental link with the TARDIS was somewhat muddied by other accounts, which showed the Doctor having a significant mental link with the TARDIS. For instance, the TARDIS assisted him with his own regeneration (DW: The Tenth Planet) and triggered a physical response in the Doctor when it was near destruction (DW: Journey's End)

All these accounts notwithstanding, the most direct commentary on the Doctor's acquisition of the TARDIS came from the TARDIS herself. (DW: The Doctor's Wife) When House transferred the soul of the TARDIS into Idris, the TARDIS was able to give her side of the story for the first time. Like other accounts, she confirmed that she was out of commission, a "museum piece", when the First Doctor met her. She also confirmed most other accounts by contending that the Doctor had stolen her, going so far as to explicitly deny the Eleventh Doctor's attempt to characterise the action as mere "borrowing". Moreover, she insisted that she also stole him. She was unlocked, and had deliberately let him steal her because she wanted to go exploring the universe and sensed that he would be an ideal match. According to the TARDIS, the Doctor's first words to her, some 700 years before, were that the TARDIS was: ". . . the most beautiful thing I'd ever known . .."

- First Doctor

Model and type
The precise model number of the Doctor's TARDIS was a matter of some confusion, especially when the Doctor's TARDIS was compared to that of other Time Lords. For instance, the Monk claimed to have a Mark IV TARDIS, while the Doctor had a Mark I. (DW: The Time Meddler) Also, the dematerialisation circuit of the Master's TARDIS was a Mark II compared to the Doctor's Mark I. (DW: Terror of the Autons) However, it was unclear whether this meant that the Master's TARDIS, as a whole, was a Mark II. During a visit by the Fourth Doctor to Gallifrey, however, the Doctor's TARDIS was unambiguously called a "Type 40". At that time, it was made clear that all other Type 40s had long since been officially decommissioned and replaced by newer, improved models. The fact that the Doctor's TARDIS was a type 40 was not common knowledge, even to the Castellan. (DW: The Deadly Assassin) This designation was used with greater frequency afterward, and was even used by the Eleventh Doctor as an excuse to Winston Churchill for his belated response to Churchill's summons. (DW: Victory of the Daleks) When the TARDIS had the opportunity to speak to the Eleventh Doctor through the body of Idris, she called herself simply a "Type 40". (DW: The Doctor's Wife)

Exterior
Almost all TARDISes were able to blend in with their surroundings because of a mechanism called the "chameleon circuit", or "camouflage unit". Some later models seemed to regularly allow the pilot to choose a desired exterior, overriding what would have been "natural" for the surroundings. (DW: Time and the Rani, Time-Flight)

In fact, the Doctor's TARDIS seemed to have both abilities, were the chameleon circuit operational. Long before he met Ian and Barbara, the First Doctor landed on Iwa, where the TARDIS quite easily posed as a boulder in that planet's desert. (TN: Frayed) Likewise, on Quinnis, the Doctor was unhappy when the TARDIS landed in a bazaar and she decided to turn into a market stall, complete with a striped awning. (CC: Quinnis) However, the Fourth Doctor showed Adric how the TARDIS could be changed to the shape of an Egyptian pyramid, implying that he could override the chameleon circuit's "automatic" functionality. (DW: Logopolis)

In any case, the defining characteristic of the Doctor's TARDIS was that its chameleon circuit had broken after assuming the shape of a police box in 1963 London. It had been working up until it landed in I.M. Foreman's junkyard. The Doctor's granddaughter stated that the TARDIS had previously appeared as a sedan chair and an ionic column, and both she and the Doctor expressed surprise that it had not changed form when they traveled to a new destination. (DW: "The Cave of Skulls")

By the time of his eleventh self, the Doctor had begun to tell his companions that the chameleon circuit was working, but in a peculiar way: "It’s camouflaged. It’s disguised as a police telephone box from 1963. Every time the TARDIS materializes in a new location, within the first nanosecond of landing, it analyses its surroundings, calculates a twelve-dimensional data map of everything within a thousand-mile radius, and then determines which outer shell would best blend in with the environment. And then it disguises itself as a police telephone box from 1963."

- Eleventh Doctor

Dangers
Eventually, friends and enemies would be able to locate the TARDIS because it failed to change shape. The Daleks (DW: The Chase) even had miniature copies of the TARDIS to use as target practice (DW: Death to the Daleks). The Cybermen also recognized it (DW: Earthshock), as did the Black Guardian's operative known as the Shadow. (DW: The Armageddon Factor) On occasion, by chance, an actual police box scared away a group of invading aliens from Earth when they mistook it for the Doctor's ship. (DWM: Useless Things)

Captain Jack Harkness was on the look-out for "a version of" the police box throughout the 20th and early 21st centuries. (DW: Utopia) Members of LINDA also knew of the outer shape of the Doctor's TARDIS, as well as Abzorbaloff. (DW: Love & Monsters)

Because of the relatively easy recognition the police box shape afforded, the Doctor made several attempts to change the exterior of the TARDIS. None of them were completely successful.


 * These attempts are chronicled at chameleon circuit.

Door
Generally, the TARDIS had two doors along one of the craft's four longer sides. Both the right and left doors could open inwardly and outwardly. A lock was on the right-hand door. On the left-hand door was a smaller door, behind which was a replica of a phone used by real police boxes to summon the police. A sign on this small door gave instructions to the user as to how the phone inside could be used. On most occasions, the left-hand door was set to a fixed position, and was not opened. Likewise, the windows on the door were most often seen in a closed position.

However, there were exceptions to all these statements.
 * The Second Doctor once effected entry through the top of the TARDIS, by lifting back a panel on which the roof lamp rested. (TVC: Peril at 60 Fathoms)
 * The lock was sometimes on the left-hand door, even though normal entry was still through the right. (DW: most serials prior to The War Machines)
 * The left-hand door was sometimes used for egress, and the right-hand one stayed in a fixed position.
 * Sometimes, both doors could be pushed (DW: Rose, Father's Day) or pulled (DW: The Runaway Bride, The Beast Below) open.
 * The emergency phone was sometimes on the right-hand panel while the Second Doctor inhabited the TARDIS, but by the time of his adventure on Dulkis, he had returned it to the left-hand door. (DW: The Dominators)
 * The windows on the doors, and around the exterior, could be opened, at least when the First Doctor was flying the Ship. (DW: The Dalek Invasion of Earth)
 * During the Doctor's first incarnation, a faded St John Ambulance logo could be seen on the door, even though sometimes it was only slightly visible under a layer of paint. However, during his second incarnation, the Doctor had it removed entirely. (DW: The Dominators onwards) When the TARDIS regenerated itself at the start of his eleventh incarnation, a new St John sticker was affixed to the door. (DW: The Eleventh Hour)
 * The exact wording on the sign on the telephone door was slightly variable over time —although once it, and the writing otherwise on the front of the TARDIS, was changed to read BAD WOLF. (DW: Turn Left) When the TARDIS "regenerated" consequent to the Tenth Doctor's regeneration, this sign became backlit. (DW: The Eleventh Hour onwards)
 * By the time he was going to have the chameleon circuit repaired by the Logopolitans, the Fourth Doctor installed a handle on the telephone panel on the left-hand door, which remained a subtle, if functional, part of the design. (DW: The Empty Child)
 * At some point prior to arriving to his unexpected death in San Francisco the Seventh Doctor affixed a small handle to the right-hand door. (DW: Doctor Who) This handle persisted even after the "regeneration" of the TARDIS consequent to the arrival of the Eleventh Doctor. (DW: Rose onwards)
 * When his TARDIS became human she asked the Doctor what the instructions were on her front door, to which the Doctor eventually replied, "Pull to open." She then asked, "Yes, and what do you do?"  The Doctor replied, "I PUSH!" followed shortly by "You know, I think I have earned the right to open my front doors any way I want!" (DW:The Doctor's Wife)

Operation
See also: TARDIS key Entry to the Doctor's TARDIS was usually effected by inserting a key into a lock, just as would be expected with a real police box. However, the locking mechanism did not respond to police-issued keys. (DW: Blink)

Originally, Susan suggested that the key forced the user to precisely insert the key or else the lock would self-destruct. (DW: "The Survivors"). At a later time, the key was isomorphic (DW: Spearhead from Space). Future usage of the key by several people other than the Doctor, or those to whom he given the key legitimately, suggested that this isomorphic property was no longer in use.

Design and features
The external design of the key changed over time. It usually appeared to be an ordinary Yale lock key. (DW: Spearhead from Space, Rose, et al) However, it occasionally appeared to have a more ornate, Gallifreyan motif. (DW: Planet of the Spiders, Ghost Light, Doctor Who)

The key could be modified to track and locate the TARDIS, allowing the Doctor to find the TARDIS if it was within a hundred years of his position. (IDW: The Forgotten) The key was known to express a link to the TARDIS by glowing and/or becoming hot to the touch. (DW: Father's Day, The Eleventh Hour)

At one point, the Tenth Doctor installed a system that allowed him to lock the TARDIS remotely using a fob (as a joke, the TARDIS roof light flashed and a alarm chirp was heard, similar to that used on vehicles on Earth). He was also able to open the door remotely. (DW: The End of Time)

Interior configuration and appearance
Periodically, the TARDIS interior went through various metamorphoses, sometimes through choice or because of other reasons, such as the Doctor's own regeneration. (MA: Invasion of the Cat-People, DW: The Eleventh Hour)

Some of these changes were physical in nature (involving secondary control rooms, etc.), but it was also possible to re-arrange the interior design of the TARDIS with ease, using the Architectural Configuration system. (DW: Logopolis, Castrovalva, DWA: 2006 Doctor Who Annual) The Fifth Doctor also called this changing "the desktop theme". (DW: Time Crash) The TARDIS was capable of doing this using a variation of the chameleon circuit. (REF: Doctor Who: The Visual Dictionary)

Roundels
The TARDIS interior walls generally consisted of roundels — circular or hexagonal indentations that lined the TARDIS console room's interior walls, and sometimes the walls deeper in the ship's interior. Some roundels concealed TARDIS circuitry and devices. (DW: The Wheel in Space, Death to the Daleks, Logopolis, Castrovalva, Arc of Infinity, Terminus, Vengeance on Varos, DWM: Kane's Story) At least one was a scanner. (DW: The Claws of Axos)

Mass
The Doctor's TARDIS was said by Romana to weigh 50,000 tonnes in Alzarius's gravity (DW: Full Circle), but presumably this is a measure of internal weight since the TARDIS was easily carried by the Marshmen. A quarter of this mass was jettisoned in order for the TARDIS to escape Event One. (DW: Castrovalva) At one point, when the TARDIS mapped its exterior dimensions onto its interior ones- making it the same size inside as it was outside-, it was even larger than Gallifrey, but given that it had been infected by the Faction Paradox biodata virus at this time this may have had an impact on its interior configuration (EDA: The Ancestor Cell).

Control room
The control or console room of the Doctor's TARDIS was that area in which the main operation of the craft was effected. It was dominated by a large, hexagonal console, typically in or near the middle of the room. Such rooms also had a scanner for viewing the outside conditions, and immediate access to the exterior ship through a set of doors. According to one source the trip from the console room to the outside required the passenger to step through the real world interface at the heart of the outer plasmic shell. (DW: Logopolis) Many other accounts demonstrated that the doors were just doors, though the TARDIS was cocooned in a breathable atmosphere. (DW: The Runaway Bride, The Stolen Earth, Meanwhile in the TARDIS, The Beast Below)

There were many variants of the Doctor's control room, and indeed the Doctor's TARDIS had more than one control room.
 * For more details, please see control room.

Library
There was also a library inside the TARDIS. (EDA: War of the Daleks, NA: All-Consuming Fire, NA: The Dimension Riders) Known books included Jane's Spaceships (EDA: War of the Daleks) and Every Gallifreyan Child's Pop-Up Book of Nasty Creatures From Other Dimensions (NA: All-Consuming Fire) and The Time Machine by H. G. Wells (DW: Doctor Who) The Murder of Roger Ackroyd by Agatha Christie (first printing, signed, with last page missing), War and Peace, The Wonderful Wizard of Oz and The I-Spy Book of British Birds (BFA: Storm Warning). At one point, the console room also incorporated a library (DW: Doctor Who).

Wardrobe
The wardrobe was where the Doctor kept some of the clothes from his previous regenerations, as well as clothing for other people. (DW: Pyramids of Mars, The Androids of Tara, The Twin Dilemma, Time and the Rani, The Unquiet Dead, The Christmas Invasion, The Idiot's Lantern). It has clothing from all times and environments in it, to suit whichever time the TARDIS' occupant(s) find themselves in. At least some of the clothes had pockets that were bigger on the inside, much like the Doctor's own pockets. (MA: Invasion of the Cat-People)

Cloister room
The cloister room was related to the cloister bell, which sounded when disaster was imminent. (DW: Logopolis, The Sound of Drums, Time Crash, The Waters of Mars, The Eleventh Hour) When the TARDIS interior went through a metamorphosis, the cloister room became a grand and gothic room with an interface with the Eye of Harmony. (DW: Doctor Who)

Holding ring
The holding ring was a storage area of the TARDIS which allowed the Doctor to preserve certain rooms. When investigated by Lucie, Susan and Alex, the ring was found to contain the rooms of many of his former companions, preserved as they were the last time the companion had been on the TARDIS. The rooms were saved in chronological order, heavily suggesting that Susan was indeed the Doctor's first companion. Susan later teased her grandfather, calling his habit of saving rooms overly sentimental. He countered by suggesting that the ring was one of the few ways that his time-travelling life allowed him to put down roots. After Susan, Alex and Lucie departed the TARDIS for new adventures on Earth, the Doctor reconsidered the wisdom of keeping so many rooms in stasis. Insisting to himself that he needed to look towards the future, he deleted all the rooms on the holding ring — "except that one". (BFA: Relative Dimensions)

Others

 * The Zero Room - A room was unaffected by the outside world. It was used as a refuge for Time Lords undergoing difficult regenerations. This room was later jettisoned so that the TARDIS could escape from Event One. (DW: Castrovalva)
 * Many companions had their own rooms, (DW: Meglos) though some lived in previously used rooms. (DW: Terminus) Some companions were seen to share accommodation. (DW: The Edge of Destruction)
 * Amy and Rory complained to the Doctor as the room he created them had bunk-beds. The Doctor defended his decision, claiming, "Bunk-beds are cool!". The Doctor may have reconfigured their room with a double bed having deleted it for extra fuel in order to enter the House's bubble universe. (DW: The Doctor's Wife)
 * There were at least 14 bathrooms. One had a leaky faucet for three centuries. Because he had misplaced his washers, the Doctor kept it from flooding the TARDIS by sealing it in a temporal bubble that made the same drops of water leak out over and over again. (MA: The Well-Mannered War)
 * There was a laboratory which Ace used to create her Nitro-9. (NA: Cat's Cradle: Time's Crucible)
 * The TARDIS had a swimming pool area which was used by Leela. (DW: The Invasion of Time) It was later jettisoned due to leakage. (DW: Paradise Towers) It was replaced some time afterward, and, following the TARDIS's crash landing after the Doctor's tenth regeneration, the water from the swimming pool fell into the library. (DW: The Eleventh Hour) He indicated that it was later repaired. (DW: Amy's Choice) However the Doctor said he got rid of it to "Give the TARDIS a bit of welly". (DW: The Doctor's Wife)
 * The box-room was a storage area of the TARDIS. (DWM: Exodus)
 * The TARDIS at one point also had extensive utility areas and corridors which, along with the swimming pool area, became battlegrounds during an attempted Sontaran invasion of the TARDIS. (DW: The Invasion of Time) The Doctor was under the impression it had been jettisoned until he stumbled across it during his tenth incarnation. (IDW: Tesseract)
 * Mel says that the Doctor used the TARDIS Laundromat to wash his clothes. (BFA: The One Doctor)
 * A food machine area was originally located near (but not in) the console room. (DW: The Edge of Destruction and others)
 * There was a zoo of endangered animals, a coffee machine and a jungle-like room. (DWM: Changes)
 * There was what appeared to be a cricket club and pitch deep within the bowels of the TARDIS. (DW: Castrovalva)
 * There was a large salon which the Doctor referred to as a "boot cupboard". When Sarah Jane Smith said that it was very big for a boot cupboard he replied, "I've seen bigger boot cupboards." (DW: The Masque of Mandragora)
 * The Doctor also possessed an art gallery containing various works of art from throughout history, (DW: The Invasion of Time) having rescued the artworks from the disasters which history states destroyed them (BFA: Dust Breeding)
 * The TARDIS had a full kitchen (BFA: Relative Dimensions) which included a refrigerator. (IDW: The Whispering Gallery)
 * There was space suitable for storing vehicles, as the Doctor was known to have kept a Vespa motor scooter in storage within the TARDIS (DW: The Idiot's Lantern). The Sixth Doctor once rented a Volkswagen and stored it in the TARDIS as well (PDA: Instruments of Darkness))
 * By the time of the Doctor's tenth incarnation, several rooms from years (and centuries) past still existed deep within the TARDIS, including the cathedral-like room where the Doctor once fought the Master (DW: Doctor Who), and a bedroom that was once used by Adric. (IDW: Tesseract)
 * It also had a sick bay, which in the Eleventh Doctor's TARDIS was up the stairs, to the left, then left again. (DW: Cold Blood)
 * It contained a drawing room, which the Doctor claimed to be his "private study" (VG: TARDIS)
 * There was a sun room which contained a sun lounger. (VG: TARDIS)
 * The TARDIS also contained a lift. (VG: TARDIS)
 * There was also a green door near the drawing room, which the Doctor told Amy not to go through. (VG: TARDIS)
 * When The Doctor was trying to get out of the universe he said he was deleting the scullery room and Squash court 7 to give the TARDIS an extra boost. (DW: The Doctor's Wife)

Specific control systems
The Fourth Doctor claimed that the TARDIS controls were isomorphic, though this appeared to have been a ruse for the benefit of Sutekh the Destroyer. (DW: Pyramids of Mars) Indeed, various companions were able to operate the TARDIS and even fly it. (DW: Castrovalva, DW: Four to Doomsday, DW: The Visitation, DW: The Five Doctors, DW: The Parting of the Ways, DW: The Sontaran Stratagem, DW: Journey's End, DW: The Lodger) The Time Lords were also able to pilot the TARDIS by remote control, usually, as the Doctor once bitterly noted, so he might take care of "some dirty work they don't want to get their lily-white hands on." (DW: Colony in Space, DW: The Brain of Morbius)

The Second Doctor once used a portable Stattenheim remote control to summon his TARDIS to him (DW: The Two Doctors). The TARDIS was also vulnerable to diversion or relocation by the Guardians, Eternals, and other immensely powerful beings such as the Keeper of Traken. (DW: The Ribos Operation, DW: Enlightenment, DW: The Keeper of Traken)

For a brief time the Fourth Doctor installed a randomiser in the navigational subsystems, though this was eventually removed. (DW: The Armageddon Factor, DW: The Leisure Hive)

The Eleventh Doctor's console
The various systems of the Eleventh Doctor's console room were fairly well-understood. According to one account, each of the six panels controlled discrete functions. (VG: TARDIS)


 * The mechanical panel contained the engine release lever, door release lever, gyroscopic stabiliser, locking down mechanism (described as a physical handbrake) and the TARDIS display dials.
 * The helm panel contained the eyepiece (an alternative to visual scanners), the time rotor handbrake and the space/time throttle.
 * The navigation panel contained a time and space forward/back control, directional pointer, atom accelerator (the spinning spiky ball) and the spatial location input (a computer keyboard).
 * The diagnostic panel contained the inertial dampers, the cooling systems (gauges), a bunsen burner and a microphone/water dispenser.
 * The communications panel contained an analogue telephone, digital com, voice recorder, analogue radio waves detector/monitor/changer and a scanner/typewriter.
 * The fabrication panel contained the materialise/dematerialise function, harmonic generator, time altimeter, a fabrication dispenser (which was described as being able to produce sonic screwdrivers and other technology - which eventually housed the Laser Screwdriver) and a Heisenberg focusing device which was used to break Heisenberg's Uncertainty Principle. This device may also have been known as a zigzag plotter.

Temporal grace
The Fourth Doctor once said the interior of the TARDIS existed in a state of "temporal grace", meaning that weapons didn't function inside the TARDIS. However, the system seemed to be malfunctioning by the time the Fifth Doctor was piloting the vessel. (DW: Earthshock, Arc of Infinity) Indeed, during his travels with Lucie Miller, the Eighth Doctor explained that the temporal grace system had not worked in years. (BFA: Human Resources) Later, Jack Harkness was able to discharge an energy weapon in the Ninth Doctor's TARDIS, and the Tenth Doctor and Martha had to actively dodge energy bolts that had been fired into the TARDIS. (DW: The Parting of the Ways, Human Nature)

Emergency systems
The Doctor's TARDIS contained various emergency systems, such as the Jade Pagoda, a 'life boat' of some description, which could in theory be piloted (NA: Iceberg), but in emergencies it would lock onto the nearest (spatially and temporally) planet with a breathable atmosphere and bearable climate. (NA: Sanctuary) The TARDIS also had a system which, when the TARDIS was left adrift in space unmanned, would automatically lock onto the nearest centre of gravity. (DW: Voyage of the Damned) There were also various emergency settings set up by the Doctor. One was set up by the Doctor as a way of rescuing his companions (but not the Doctor himself) if the Doctor's death seemed inevitable, transporting the TARDIS (with the companion inside) back to the companion's respective time and home. This is called Emergency Program 1 (DW:Bad Wolf, DW: Silence in the Library). Another could reunite the TARDIS with the Doctor if they were separated; however it required another individual to enter the TARDIS and insert an 'authorised command disk' to activate it in the first instance (DW: Blink), after which it seemed to have been installed and fully integrated into the ship's systems; the TARDIS automatically commenced the emergency programme without external aid in various attempts to reach the Doctor, who had been trapped in a time-loop (SJA: The Wedding of Sarah Jane Smith).

The TARDIS also contained a switch labelled "LTD" (standing for "Locate The Doctor"). This was used by Lucie Miller in BFA: The Beast of Orlok.

The TARDIS was also capable of extensive self-repair, for example after suffering a hull breach or having been deposited into a core of z-neutrino energy. (DW: Voyage of the Damned/DW: Journey's End) In case of more extensive damage - more than 1 second before termination (by z-neutrino energy) apparently - a complete rebuilding would take place, effectively changing the entire interior and exterior appearance (DW: The Eleventh Hour); a forced change of "desktop theme" if you will (among others: Tardis coral). The TARDIS has an alarm system known as the cloister bell that activated in dire circumstances. (DW: Logopolis, Doctor Who, Turn Left, The Waters of Mars, The End of Time)

Another emergency program activated when the TARDIS exploded. This particular program locked the control room in a Time loop to protect its inhabitants. (DW: The Big Bang) There is also a safety mechanism when TARDIS rooms are deleted, which automatically relocates any living beings present in the deleted room, depositing them in the control room. (DW: The Doctor's Wife)

Defensive systems
Beyond the chameleon circuit, the TARDIS could teleport itself a short distance away from its current location if it was being attacked. The Doctor called this the Hostile Action Displacement System (HADS). (DW: The Krotons)

A related system was meant to protect the TARDIS from landing in the path of oncoming vehicles, by preventing it from landing on, for example, train tracks. This feature failed when the TARDIS landed on train tracks in Vichy France. The Second Doctor, Ben, Jamie and Polly had to physically push the TARDIS out of the railway bed before the next train came down the tracks. (CC: Resistance)

The TARDIS was at one point temporarily given a defensive shield utilizing a Tribophysical waveform macro-kinetic extrapolator. (DW: The Parting of the Ways)

Offensive systems
The TARDIS later gained some offensive systems of sort; although this could have been caused by its development into the Edifice. This weapon allowed the Edifice/the Doctor's TARDIS to destroy Gallifrey, although this was only accomplished by channelling all of the Edifice's energy into the weapons. (EDA: The Ancestor Cell)

Intuition circuits
Using a holographic representation of the universe connected to the TARDIS' neural net, the TARDIS was effectively able to make hunches, guesses where it needed to be. Though the TARDIS was able to guess where it was needed, it was unable to inform the Doctor of what he needed to do once he got there. (VD: ...And Eternity in an Hour)

Other systems

 * The TARDIS appeared to be able to lock onto the presence of another Time Lord, particularly the Doctor's family, even when doing so would create a temporal paradox. (DW: The Doctor's Daughter)
 * The Doctor made modifications and additions from time to time. For example, at one point the TARDIS was equipped to write computer files to standard Earth CD-ROMs (DW: World War Three), and he also at one point modified the control console to accept DVDs in order to allow Sally Sparrow to use a specialized control disc to activate the TARDIS (DW: Blink).
 * It could be put one second out of synch with time. The Tenth Doctor did this once in order to prevent the Master from taking it. (DW: The End of Time)
 * The TARDIS possessed the ability to allow both the Doctor and others to understand a wide variety of languages. (DW: The Christmas Invasion) See separate article for a more in-depth discussion.
 * The TARDIS had a link to the Matrix. Following the Last Great Time War, this Matrix was the only one left. (IDW: The Forgotten)
 * It had stabilizers activated by blue buttons. These were first used by River Song, though it was unknown if the Eleventh Doctor previously knew about these or not. He said that they made the journey no fun. (DW: The Time of Angels)
 * It had brakes, which, according to River Song, were always on, which is why the TARDIS landed with a characteristic wheezing noise. When she landed the TARDIS without the brakes on, it landed without any sound. (DW: The Time of Angels)
 * It had buttons for Ketchup and Mustard. (DW: Vincent and the Doctor)
 * The TARDIS had a part called the "rectifier". (DW: The Lodger)
 * The TARDIS' engines automatically shut down when there were no longer any people in the craft. (DW: The Pandorica Opens)
 * The TARDIS had the ability to become invisible, but such a feature was a drain on its power reserves. (DW: The Impossible Astronaut)
 * The TARDIS had 'telepathic circuits' that could transmit messages to individuals through their thoughts. (DW): The Doctor's Wife).
 * The TARDIS could alter the environment within its rooms and even fast-forward time within itself (or at least create the illusion of time passing). (DW: The Doctor's Wife)
 * The TARDIS could stabilise the bodies of the Gangers, simply by virtue of them entering the Control Room.(DW: The Almost People)

Personality
As TARDISes were intelligent, the Doctor's TARDIS had also developed a personality. It was called "sentimental" by the Eighth Doctor (DW: Doctor Who) and "stupid" by K9 (DW: The Invasion of Time). Though intelligent, it was generally unable to communicate in words with the Doctor, relying on other methods of communication. (DW: The Edge of Destruction, The Runaway Bride) Even when the TARDIS did not take the Doctor where he wanted to go, it took him where it felt he needed to be. (DW: The Doctor's Wife)

The TARDIS also displayed a prejudicial fear of the time-locked Jack Harkness. (DW: Utopia) The TARDIS showed a similar hostility to Charley Pollard when she began to travel with the Sixth Doctor (BFA: The Condemned), apparently due to the paradoxical nature of her very existence. (BFA: Storm Warning) This resulted in the TARDIS 'refusing' to protect Charley from viruses, as it had protected his previous companions. (BFA: Patient Zero)

When the Doctor's history was changed so that his third incarnation regenerated ahead of schedule, the TARDIS sensed that he had been infected with the Faction Paradox biodata virus, which threatened to turn him into a member of the Faction. The TARDIS thus took the infection into itself, holding itself together even after being nearly torn apart in a dimensional anomaly. (EDA: The Shadows of Avalon) Had it not, the Doctor would likely have become corrupted by the Faction.

When the Tenth Doctor was attacked by Es'Cartress‎, the TARDIS tried to help him in the Matrix, taking the forms of his companions and helping him regain his memories. (IDW: The Forgotten)

The Doctor responded to the TARDIS' personality by showing it great tenderness. He referred to it as his "dear old friend" on one occasion. (DW: The Deadly Assassin) The Eleventh Doctor was overtly demonstrative towards it, calling it both "dear" and "you sexy thing" shortly after its own regeneration. (DW: The Eleventh Hour) In many of his incarnations he anthropomorphized it by referring to the TARDIS as "she" or "her". Indeed, at least one account suggested that it wasn't a colloquialism: the TARDIS actually was female. (ST: The Lying Old Witch in the Wardrobe)

The TARDIS had a female-like personality when she was transferred into a humanoid body of Idris. While in this form she thought Rory was "pretty" and stated that she chose the Doctor as a companion and that she "love[d]" him. She also referred to the TARDIS remains in a junkyard as "her sisters," which implied that all TARDISes were female. (DW: The Doctor's Wife)

Behind the scenes

 * The ubiquity of the TARDIS to the Doctor Who franchise was recognized in late 2009 when the BBC unveiled a new version of the Doctor Who logo which began to be used in 2010; the logo incorporates the initials DW formed in the familiar police box shape of the Doctor's TARDIS.
 * Although the TARDIS has been a constant presence in the series since 1963, it has almost always been essentially a mode of conveyance, with the majority of stories taking place away from the vessel. There have been a few exceptions, such as DW: The Edge of Destruction and Time Crash in which the entire action of a story takes place within the TARDIS. DW: The Invasion of Time was the first story to give viewers an extensive tour of the bowels of the TARDIS (other than occasional prior glimpses of individual rooms); a more modest "tour" occurred in DW: Castrovalva. Viewers also saw new aspects of the TARDIS in the 1996 TV movie. In the comic strips, several stories have taken place almost entirely within the TARDIS, including DWM: Changes and IDW: Tesseract. In DW: The Doctor's Wife, more of the TARDIS was actively explored (albeit very similar areas) and parts of said areas were used by the antagonist to attempt to trap or kill the inhabitants.
 * The Doctor's TARDIS also appeared in the video game Fallout, in a random encounter.