Touted as the world's biggest underground depot, it officially opened on 4 March 2009, employing 300 staff members.

[2] The depot was used for the temporary storage and light maintenance of rolling stock for the Downtown line, before the completion of the Tai Seng Facility Building.

It also houses an automatic storage and retrieval system, a warehouse that stores spare parts for the rolling stocks and other equipments.

The extension called for the depot to be expanded underground to almost double its land area and stabling capacity from 70 to 133 trains.

[5][6] The Contract 821A for the construction of Kim Chuan Depot extension and its associated facilities was awarded to Woh Hup (Private) Limited at a sum of S$1.21 billion in September 2017.