I.M. Foreman's Travelling Show
I.M. Foreman's One-Species Nongenetically Engineered Travelling Show is a complex space-time event. It is similar to, although not like, a TARDIS.
Piloting and Travel
I.M. Foreman programmed the show's course by meditating and communicating telepathically with it.
It is a space-time vessel but it has no extra-dimensional connections. It moves through space and time by retroactively building a site and disguising itself before/during/as it moves there. This process takes years.
It is not designed for instantaneous (or even fast) travel, unlike a TARDIS. Unlike most TARDISes, the show can travel back into the Dark Time, and does so, its occupants proof of it. (EDA: Interference: Book One, Interference: Book Two)
Effects the show has on space time
A by product of this is that it sometimes knocks dents in space time which lures other space time travellers to the site. Such as: the Faction Paradox, The Remote and the Third Doctor and Sarah Jane Smith to the planet Dust. Also the First Doctor and Susan to Earth, 76 Totter's Lane, 1963.