Temporal engine

Temporal engines were devices that allowed multiple different timelines to exist simontainiously. Known engines were kept in the Red Waterfall facility for Chen-7 on Apalapuchia, which allowed more than 4000 timlines to exist in seperate realities. Exhaust from the engines prevented Handbots from locating patients, such as the accidentally-admitted Amy Pond. (DW: The Girl Who Waited).