It was necessary to proceed extremely carefully with the demanding second of three drives with a total length of 850 meters: the foundations of the Trinity Church in Offenburg, South Baden, had to be passed under with an overburden of only 3.5 meters. So that the two 50-meter high church towers of the over 100-year-old building did not develop a tilt, the work was preceded by intense geological examinations. The new channel collects up to 85 percent of rain and contaminated water, and conveys it to the sewage treatment plant.

The solution was a Herrenknecht machine with partial-face excavation, which tunnelled the mixed water channel using pipe jacking technology. To avoid settlement, a bentonite suspension immediately behind the shield supported the so-called overcut (the excavation cross section is somewhat larger than the tunnel diameter). On June 23, 2006 the machine completed the second stage of its work, having driven 405 meters through loam and sand with a diversion of less than one centimeter and with no damage to the church.