Spotted! Liebherr crane… 2020m up in the Swiss Alps
This LTR 1060 telescoping crawler crane faced a long climb before getting to work on Europe’s second-highest mountain railway
When a mobile crane was needed for work on extending a rail tunnel high in the Swiss mountains, the first problem was how a crane could be transported up the winding and narrow road.
Rental company Clausen Kran decided to use a Liebherr LTR 1060 crawler crane with telescoping boom, and drive it up the slope. The crane had to traverse a gravel track with tight bends and steep slopes with gradients of up to 40 percent, over 920 metres with an ascent of 180 metres. The company turned to Liebherr for advice on feasibility. The Liebherr team calculated the overall centre of gravity of the machine to ensure that it would not tip over and would remain manoeuvrable when travelling around the bends and up the gradients. The results showed that the LTR 1060 would be able to travel along the route without ballast at a gross weight of 38 tonnes and the boom at an angle of 20 degrees. In addition, the hook block had to be secured to prevent swinging.
The narrowness of the path meant that the crawler crane had to negotiate the snaking route with its crawler chassis retracted. This meant steerability was severely restricted, as a result of the poor ratio between crawler length and track width. To allow the vehicle to be steered in the tight bends, one-metre lengths of square timber were placed under the inner crawler chains to act as pivots.
Gear box and roller overheating was another concern, and Liebherr Biberach advised that the oil level should be slightly reduced in the gearboxes, to reduce splashing losses caused by the oil being swirled around. As a result, temperatures remained well below maximum values; they were monitored by the crane owner with a thermal camera as the crane ascended.
Driving the 940-metre route took two hours, though the final few metres had to be driven in reverse to give the crane easier access to the site.
The crane was then able to carry out the job, working on a tunnel extension for the Gornergrat rack railway, Europe’s second-highest mountain railway.
