27.10.2014

Mountain climbing crawler

Swiss rental company Clausen Kran has driven its new 60 tonne Liebherr LTR 1060 telescopic crawler crane to the top of an Alpine mountain to work on the one of the highest railway tunnels in the Alps.

The crane had to travel almost a kilometre on gravel tracks, negotiating tight bends and gradients of up to 40 percent to the reach the 2,020 metre high site - a tunnel on the Gornergrat railway in Zermatt. The second-highest mountain railway in Europe, the tunnel is being extended to allow a downhill ski run to pass over the tunnel so that in the future it can stage FIS skiing events.
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The road up to Zermatt had other challenges including low bridges

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In Zermatt the crane and truck crossed a small bridge independently

Clausen is used to working with cranes in high Alpine terrain but the challenges for this job were such that it called on the Liebherr engineering team for assistance.

The overall centre of gravity of the machine was calculated to ensure that it would not overturn, 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 and a gross weight of 38 tonnes with the boom at an angle of 20 degrees. In addition the hook block had to be secured to prevent it swinging.

The crane was moved by low loader through Zermatt in the early morning – a challenge in itself - involving the crossing of a small bridge. The LTR 1060 was unloaded just before reaching the crossing and the two vehicles were then driven across the bridge individually. The LTR 1060 was then reloaded and taken as far as the truck could go, reaching an altitude of 1,840 metres.

At this point company owner Geri Clausen himself got into the crane cab and began the two-hour journey up the mountain. The final few metres had to be driven in reverse to enable the crane to access the site more easily.
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The crane begins the dive up the final kilometre

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Grades were as much as 40 percent

The narrow track also forced the crane to travel with retracted tracks, creating a poor ratio between the crawler length and track width, making it less manoeuvrable. To allow the vehicle to get around the tighter bends, one metre timber squares were placed under the inner track to act as pivots. Another recommendation from Liebherr was that the direction of travel of the crawler chassis should be selected so that the chain drives were at the rear to ensure that the crawler chain remained taut on the ground at all times.
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And included tight bends

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The last few metres were driven in reverse

Another challenge was the danger of overheating the transmission and rollers due to the high loads imposed by the long, steep route. Liebherr’s general manager of engineering, Hans-Dieter Willim, visited the site himself to check the temperature of the critical components with a thermal camera. Having spoken with the Liebherr team that designed and manufactured the transmission, he decided to reduce the oil level slightly in the gearboxes to reduce splash losses. The temperatures remained well below the maximum values.

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Finally on top of the world with a view of the Matterhorn

Clausen said: “We have lots of sites where this highly manoeuvrable crane is simply perfect.”

Clausen Kran, a family company, was founded in 1972 in Brig in the canton of Valais. The company runs a small, mostly Liebherr mobile crane fleet ranging from the 55 tonne LTC 1055-3.1 city type crane, to a 220 tonne LTM 1220 5.2.