Kuyambitsa KJ421 Hydraulic Tunnel Boring Rig - yankho lomaliza pazosowa zanu zonse zotopetsa. Makina obowola akuluwa amapangidwa mwapadera kuti akumane ndi ma tunnel amitundu yosiyanasiyana, okhala ndi magawo oyambira 16-68 masikweya mita. Chobowoleracho chimakhala ndi mphamvu zobowola kwambiri, chimatha kubowola mabowo ndi mabawuti moyima, molunjika komanso mopingasa, ndipo ndi chida chofunikira kwambiri pomanga ngalande.