Temporal engine
From Tardis Wiki, the free Doctor Who reference
Temporal engines were devices that allowed many timelines to exist simultaneously, There were temporal engines in the Red Waterfall facility for Chen-7 on Apalapucia which allowed more than four thousand timelines to co-exist. Exhaust from the engines prevented Handbots from locating patients, such as the accidentally-admitted Amy Pond. (DW: The Girl Who Waited).
