Work to place the first piles for the northern stretch began in July 2019. Huge machines drilled holes up to 20 meters deep in the ground for all 135 of them. The drill heads used were 1.2 meters in diameter. Each of the 13-meter-tall supports rests on at least four such piles to ensure a stable base. In all, the construction workers placed 47 supports and 17 frames for the northern stretch. (Project head Wolfgang Holzhausen reports on construction of the new Sky Line route.)