It is a project of superlatives: a tunnel borer 12.07 meters in diameter cuts its way down to a depth of 74.83 meters beneath the Yangtze River with ground conditions characterized by high water permeability, high compactness and high quartz content. Maximum external pressure: 9.8 bar. And as if that were not enough: Methane deposits. “We have built plenty of tunnels before, but this one sets new standards in many respects,” says Chen Peng, Project Manager at China Railway 14th Bureau Group Co., Ltd. So it was all the more important that everything went right from the very first day: in only seven and a half months the experts from Herrenknecht and the 14th Bureau Group Co., Ltd. designed and built a machine that could meet the complex specifications of this contract.