Time corridor

A time corridor, also called a time-space induction channel and sometimes referred to as a time tunnel, was a form of time travel in which a wormhole was created through the Time Vortex, linking two points together. It was generally considered less advanced than other time travel technologies such as TARDISes. (TV: Timelash) Considered child's play by the Seventh Doctor, one of the basics of time corridor technology was anchoring the exit point, since time corridors were temporary and collapsed when their power was cut. (PROSE: Set Piece) It was similar in concept, though not identical, to a wormhole. (AUDIO: The Dead Star)

The Time Vortex was also referred to as a time corridor (PROSE: Timewyrm: Revelation) which may have accounted for the danger of creating other corridors through the Vortex. Kontron tunnels were time corridors in space rather than the Vortex. (TV: Timelash)

Time corridors were primarily used by the Daleks. Despite being described as less advanced than other time technology, time corridors seemed to be easily capable of dragging a TARDIS off course to a specific location. When he fought against the two antagonistic Dalek factions - the Renegade Daleks and the Imperial Daleks who were trying to steal the Hand of Omega so they could at last gain the power of the Time Lords and improve their methods of moving through time, the Seventh Doctor described their time corridor technology as "very crude and nasty." (TV: The Evil of the Daleks, Resurrection of the Daleks, Remembrance of the Daleks)

Time corridor technology was first used by the Daleks near the beginning of the Great Civil War. (TV: The Evil of the Daleks)

The Seventh Doctor transferred a time tunnel to the Greenwich Meridian to counter a trap by. (TV: Dimensions in Time)

In order to complete a corridor, the Daleks at first built time conduits that would serve as the ends of the corridor. If the conduit on a planet was destroyed, the Daleks would no longer be able to reach it via the time corridor. (AUDIO: The Mutant Phase) Later Dalek time corridor devices, like the Time Controller, were portable and could remotely establish corridors between selected temporal coordinates. (PROSE: Dalek Combat Training Manual)

The Daleks used a time corridor as a link between themselves and Earth in 1984. There they had deposited samples of the Movellan virus that they would later need. Turlough accidentally travelled through the corridor and so the Doctor followed him in his TARDIS. Both the Daleks and Lytton's men used the corridor numerous times. (TV: Resurrection of the Daleks)

Two Dalek Strategists and Dalek pilot escaped in a Time corridor. (AUDIO: The Time of the Daleks)

The New Dalek Paradigm used a time corridor to escape destruction at the hands of Eleventh Doctor and Danny Boy. The creation of the corridor was very rapid, and when the Dalek saucer entered the corridor, it seemed to jump through space, stretching the stars as it escaped. (TV: Victory of the Daleks)

The Sontarans were also developing time corridor technology, constantly improving their advancements whereas the Daleks, at least according to the Sontarans, assumed they achieved perfection and so did not improve their methods. (AUDIO: The Five Companions)

In emergencies, some crafts travelling within a time corridor could deploy an escape time corridor which could latch onto familiar technology. (AUDIO: The Time of the Daleks)

The Osirans had developed a form of time corridor by making use of time spillage, but use of these corridors aged them the same amount that they travelled through time. While this was less of a problem for them than it would have been for other races given their exceptionally long life-spans, it was exploited by the Fourth Doctor trapping Sutekh in a corridor extending into the far future (TV: Pyramids of Mars) and the Fifth Doctor tricking Nephthys into making a constant series of 140-year round trips until she had aged herself to death. (PROSE: The Sands of Time)

The Council of Eight made use of time corridor technology and they used them to despatch agents through history to ensure predicted events occurred as they had foreseen in a universe where the Time Lords were gone. The corridors the Council used were deliberately unstable and the agents would throw anything and anyone deemed unimportant to history into the corridor entrance, where they would be torn apart by time winds. (PROSE: Sometime Never...)

In the 41st century, George Sheldrake developed time tunnels using the temporal velocitor from the Nun’s TARDIS. (AUDIO: The Wrong Woman)

The fractured Eternity Clock created time corridors in four different eras of London, releasing the Silence in the Elizabethan Era, Silurians in the Victorian Era, Cybermen in modern-day London and the New Dalek Paradigm in 22nd century London. The Eleventh Doctor and River Song travelled between these different times and collected the pieces of the Clock, which closed the time corridors and erased the alternate timelines created by the invading species. (GAME: The Eternity Clock)

The Eleventh Doctor accidentally jettisoned a room once, inadvertently creating a time corridor and allowing shadowy creatures to pass through and arrive in 1964. They were drawn to Earth because Ethan dropped his mobile phone in 1964, despite coming from 2014, which made them hungry. (COMIC: The Door to a Winter Long Ago)

The Quire used a time corridor to travel to the Braxiatel Collection. (PROSE: Work in Progress)

After crossing paths with the Nun, George Sheldrake harvested components from her TARDIS to build time tunnels, (AUDIO: The Wrong Woman) which he intended to release to the public, something that was far beyond the capabilities of 41st century humanity. (AUDIO: Buying Time) Posing as the Doctor, the Nun managed to steal back her temporal velocitor, causing the tunnels to spiral out of control when they were activated. The Tenth Doctor managed to stabilise the tunnels, even abducting his past self to set him on the path to stop them, before he shut them down completely. As the temporal chaos had destroyed all the evidence of Sheldrake's involvement, the Space Security Service was unable to legally detain him, thought the Doctor noted that the public would blame him for the failure of his highly publicised tunnels and sue him into bankruptcy. (AUDIO: The Wrong Woman)

Behind the scenes
According to the invalid source, Doctor Who: The Dalek Handbook, after the end of the civil war and the defeat of the Humanised Daleks, the Emperor Dalek decided that the Daleks, in order to succeed in their conquests, would have to change history, thus time travel was put into greater use by the race.