Electrification of the AKN line S5 – Earthing of four new structures

Initial situation

The AKN line S5 between Eidelstedt and Kaltenkirchen is currently operated using diesel locomotives. The 30 km section from km 4.4 to km 34.5 will be electrified and expanded to double track operation. As part of this project, several structures along the route are being renewed and must be earthed to ensure electrical safety.

Services

As part of the track electrification, a second track will be added near the Gronau bridge. To minimise line closures, a new bridge with a new track will be constructed alongside the existing bridge. The old bridge will then be demolished and rebuilt, including the track system. This phased construction ensures that a section of the line remains operational throughout. Since the two bridge sections are being constructed in different phases, a key aspect of the design involved planning the connections so that both structures would be interconnected in the final state, with a unified earthing system for the entire structure.

The Viehtrifft culvert, which runs beneath the railway line, is also being renewed. Therefore, a new earthing system was designed for this structure as well. Like the Gronau bridge, the Viehtrifft culvert lies in the alternating current section of the line. Consequently, the design process incorporated the Deutsche Bahn AG guideline module group 997.02 for 16.7 Hz railway power supply systems, guideline DB-Ril 804.9030 and DIN EN 50122-1.

The grade-separated junction consists of a trough structure made up of several reinforced concrete trough sections, a reinforced concrete slab on micropiles and a reinforced concrete slab on bored piles. On one side, the structure connects with the Weidplan railway overpass, which runs beneath the railway line. The earthing design for these two new structures was also part of our contract. On the opposite side, the earthing integration with the existing flyover structure and the retaining wall along Lampéstraße had to be considered. Since both the grade-separated junction and the Weidplan railway overpass lie within the direct current section of the line, different standards had to be applied in part. In particular, the DB-Ril 998.02 guideline module group, DIN EN 50122-1 and DIN EN 50122-2 were observed.