Out with the cable scrap from the River Aare

From the 10th until the 12th of June 2009, Atel Transmission Ltd fished two, more than 50 years old, high voltage cables from the bed of the River Aare near Rankwaage near the village of Winznau. The work was carried out using an excavator mounted on a 100 ton floating container. The removal was done to protect the environment.

Atel Transmission Ltd: 520 metres of high-voltage cable fished out of the Aare.

The two 16 kV high voltage cables that led to the old Rankwaage substation, had been submerged in the River Aare since 1958. One cable was 380 metres in length, 73 millimetres thick and ran in loops upstream. The other measured 140 metres in length, 98 millimetres in diameter and ran parallel to the Gösgerstrasse Bridge. Together, the two cables weighed around 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, new cables were laid on the bridge and the old cables were hence taken out of service.

From the 10th of June 2009, an excavator mounted on a floating container retrieved the cables metre by metre from a depth of some four to six metres. Subsequently the cables were cut up and disposed of. "This is the first time that we have done something like this", said 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." Two days later he had the assurance that everything had gone according to plan.