Time track
A time track was a path through time. "Jumping" a time track could place a time traveller off their intended destination in time, possibly even crossing their own destiny lines.
History
The First Doctor jumped a time track in the TARDIS that allowed him and his companions to view an alternate timeline in which they had becomes exhibits in the Moroks' Space Museum on Xeros. (DW: The Space Museum)
The Fifth Doctor's TARDIS jumped a time track and was thrown through a Time corridor, ending up in an alternate timeline where the Daleks mutated into insectoid monsters. (BFA: The Mutant Phase)
When the TARDIS once landed in between times, in a time where this was no time, the Eighth Doctor believed that he and his companions had jumped a time track. (BFA: Time Works)
The Ninth Doctor and Rose chased a Chula ambulance through the time vortex. It began jumping time tracks and the Doctor lost it for a while. He managed to find where it landed and believed it to only have landed, at maximum, a month before he and Rose arrived. (DW: The Empty Child)
The Tenth Doctor jumped a time track in the TARDIS that allowed him to visit the Dalek time period before the Last Great Time War. (NSA: Prisoner of the Daleks)
The Eleventh Doctor suspected that the TARDIS slipped a time track when he, Amy and Rory were having several dreams, before discovering it was the work of psychic pollen which had fallen into the TARDIS' time rotor. (DW: Amy's Choice)
Behind the scenes
- In the 1993, thirtieth anniversary special, generally considered un-canon, the Seventh Doctor was trapped by the Rani, and was jumping time tracks between the years 1973, 1993, and 2013. During this time, he jumped back and forth between his third, fifth, sixth and seventh incarnations, while Ace, his then present companion, kept being replaced by various past companions.