Nendaz-Veysonnaz is part of the "4 Vallées" winter sports region around Mont-Fort in the canton of Valais, south-east of Lake Geneva. It is the largest in Switzerland and offers 412 kilometers of slopes for skiers and snowboarders at an altitude of between 821 and 3,300 meters. The season starts in December and lasts until April and May, depending on snow conditions. Two T-bar lifts lead up to the 2,700-metre-high Greppon Blanc: the "Greppon Blanc 2" is an anchor lift and the "Greppon Blanc 1" is a platter lift. There was a technical defect in the valley station of this lift in March 2019.

Analysis in the ski area

In the evening, those responsible at the operating company Nendaz-Veysonnaz Bergbahnen AG noticed unusual running noises and an increased temperature on the gearbox and informed the company Baco AG from Steffisburg near Thun, which is responsible for servicing the ski lifts. As they did not want to risk either the safety of the skiers or a lengthy interruption to operations, Alfred Imhof AG was asked to carry out a rapid analysis and diagnosis. The company represents SEW-Eurodrive products and solutions in Switzerland and is the first point of contact there when it comes to drive technology.

The very next morning, specialists from Alfred Imhof AG met for a meeting. It quickly became clear that an on-site vibration measurement, oil analysis, thermography and endoscopy were necessary to make a meaningful diagnosis. Once the customer had approved the proposed condition monitoring measures, two service technicians set off for Nendaz on the same day. From there, they were taken to the site by four-wheel drive vehicle, gondola and snowmobile. In their luggage: special work clothing with cold protection and eight cases with special tools. The two experienced technicians carried out a detailed problem analysis. The findings were: several teeth were broken on the bevel pinion and several teeth were defective on the second gear stage. For safety reasons, the ski lift was only allowed to continue operating with restrictions for the time being.

Support from the air

There was only one possible solution to quickly rectify the damage: repairing and replacing the defective parts. The required spare parts were immediately ordered in Finland. SEW-Eurodrive operates its own plant for industrial gear units there. The delivery was made by air freight due to the high time pressure. For logistical and organizational reasons, the repair was carried out at Alfred Imhof AG in Münchenstein near Basel.

After properly disposing of 99 liters of gearbox oil, the customer removed the 1.3-tonne gearbox together with the cable car manufacturer's service partner and flew it by helicopter to the valley station in Siviez, a village in the municipality of Nendaz. From there, the complete gearbox was transported by jeep and trailer to Imhof AG in Münchenstein.

The repair was carried out on the following two days. The gearbox was then repainted to protect it from corrosion. A few more functional tests were carried out before it was transported back to the ski resort. Once there, the gearbox was flown back to the ski lift by helicopter, where it was reinstalled by NVRM employees and the two service technicians from Alfred Imhof AG. After commissioning and handover to the customer, the ski lift resumed operation as usual.

Successful repair

The service interruption lasted six days. A long time for a mountain railroad that wants to transport its customers. Peter Baumgartner, Product Manager at Alfred Imhof AG, explains why this was the fastest possible solution under the given circumstances: "The spare parts had to be flown in from Finland and installed in our workshop. Thanks to our many years of expertise in the ropeway industry, we were able to respond quickly and competently in terms of advice, problem analysis, finding a solution and rectification. The cable car operator put the safety of its passengers first and accepted the interruption to operations lasting several days." dsc