The original proposal called for deep subway tunnels that can better serve military functions. Between Gongzhufen and Muxidi, shafts as deep as were being dug. The world's deepest subway station at the time in the Kyiv Metro was only deep. But Beijing's high water table and high pressure head of ground water which complicated construction and posed risk of leakage, and along with the inconvenience of transporting passengers long distances from the surface, led the authorities to abandon the deep tunnel plan in May 1960 in favor of cut-and-cover shallow tunnels some below the surface.