Old workshop

The "old workshops" were the location on Gallifrey where TARDISes could be built or repaired. It was connected to the Cloisters of the Matrix. (TV: Hell Bent) Indeed, according to The Book of the War, because the caldera, as an "absence" in the fabric of the universe, was the only place where the non-linear processes necessary to the creation of new timeships could be harnessed, a "null-zone" connected to the crater site was created for the purpose, and came to be referred to as a "kind of 'womb'", (PROSE: The Book of the War) and which the timeships themselves called "Mother". (PROSE: Toy Story)