The No.7 tunnel along the Jakarta-Bandung High-speed Railway, constructed by China Railway No.3 Engineering Group Co., Ltd. (hereinafter referred to as “CR3”) was dug through on November 15, marking a major breakthrough in the construction of the rail line. It is the fourth tunnel that has been cut through along the railway under construction, as well as the first extending for more than 1,000 meters.

It is a single-cave, two-line tunnel, with a total length of 1,285 meters. The area features volcanic lime mudstone, with 80 percent being V-class surrounding rocks and 93 percent buried 30 meters or more underground. The area also suffers high water permeability and frequent slope slips and geological deformations. For this reason, the entrances on both ends suffer broken rock masses, increasing difficulty in constructing the tunnel.

With a total length of 142.3 kilometers, the Jakarta-Bandung High-speed Railway has a maximum design speed of 350 km/h. It will cut the travel time between Jakarta and Bandung from the current 3-plus hours to 40 minutes. (Source: CR3)