The excavator on the floating container will retrieve the cables piece by piece from a depth of some four to six metres. Subsequently the cables will be cut up and disposed of. "This is the first time that we have done something like this", says the Project Manager Georg Müller from Atel Transmission Ltd. "We do not know exactly how deep the cables have been buried by the sediment transport on the river bed. Hence it is still uncertain how much time we will need."
The two 16 kV high voltage cables that lead to the old Rankwaage substation, have been lying in the River Aare since 1958. One cable is 380 metres in length, 73 millimetres thick and runs in loops upstream in the Aare. The other is 140 metres long, 98 millimetres in diameter and runs parallel to the Gösgerstrasse Bridge. Together, both cables weigh approximately 4,000 kilograms. With the building of the new substation between the Rankwaage Bridge and the weir, and the reconstruction of the Hauenstein railway bridge in 2008, AVAG laid cables on the bridge and the old cables were hence taken out of service.