At nearly 2,000m above sea level, Wolffkran’s XXL luffing cranes completed one of Europe’s most challenging dam construction projects. Now, after 32,000 lifts and 500,000 tons of concrete, the team and its machines are headed from the Swiss Alps to Saudi Arabia.
Engineering at altitude
The new Spitallamm Dam at Grimsel Pass in Switzerland was officially inaugurated in June 2025, closing a chapter of Alpine construction that pushed cranes, operators and engineers to their limits.
For project manager Ralph Stump and a team of six operators, it marked the culmination of four and a half years working at almost 2,000m above sea level. Two WOLFF 1250 B luffing cranes, each nearly 100m tall and mounted on pile foundations weighing more than 1,500 tons, moved approximately 500,000 tons of concrete in 32,000 lifts.
To meet the unique challenges of altitude, Wolffkran developed the TV 60 tower element with six-metre side length — a design capable of withstanding extreme Alpine weather while allowing the cranes to operate freestanding.
Teamwork in extreme conditions
The project demanded a relentless schedule: a short May–October building season, 24/7 operation, and crews working in three shifts of eight hours each. Operators contended with sudden fog, snowfalls measured in metres, avalanches and storms.
“Behind all these superlatives stands a unique team effort,” said Stump. “If the call came at 10:30am that a rope had to be replaced, our installers had the spare part up on the crane by noon. By 5:30pm operations were running again. Seven days on, three days off, eight hours per shift in the crane – a truly demanding assignment.”
Tasks included replacing 120kg bolts at heights above 90m and swapping hoist ropes twice per season. Despite the strain, morale remained high — two women and four men operated the cranes, and all described the project as a career highlight.
On top of all this comes the special challenges of operating in the mountains: dense fog within minutes, meters of snow overnight, avalanches and storms. Nevertheless, all WOLFF employees remained highly motivated. “If the call came at 10:30 am that a rope had to be replaced, our installers had the spare part up on the crane by noon. By 5:30 pm operations were running again,” says Stump.
“Replacing a 120-kilo bolt at over 90 meters height on the crane – here, too, our team was on site. Despite the demands, interest in this job was high, and all of the six crane operators – two women and four men – are proud to have been part of this special project.
Dismantling began in October 2024, and by June 2025 the last parts were transported down into the valley. A total crane volume of 4,205 cubic meters with a total weight of 1,281 tons was distributed over more than 60 truck journeys, some with oversize loads.
The success of the deployment owed much to Wolffkran’s overwintering system, which automatically moved the cranes three times a day while insulated with specialised mats. This ensured they were ready to move directly to their next assignment without delay.
Next stop: Saudi Arabia
In addition to team, technology and logistics, the sophisticated over-wintering concept also proved invaluable. Each crane was automatically moved three times a day during the winter season, i.e. the hoist winch, luffing gear, and switch cabinet were wrapped with special insulation mats.
This colossal effort really paid off, as the WOLFF cranes were able to proceed directly from their Alpine assignment to their next construction site: the cranes are now bound for the Prince Mohammed Bin Salman Stadium in Qiddiya, Saudi Arabia.
Like the Alps, the site is located on exposed terrain with challenging conditions — again requiring 100m freestanding tower heights.
The Spitallamm Dam attracted significant international attention, with visits from engineers and construction leaders keen to see Wolffkran’s red giants in action. Beyond the numbers, the project showcased how a combination of technology, logistics, and team resilience can deliver results under the harshest conditions.
Chances are high that the experiences gained at the Grimsel Pass will also feed into future construction projects.
“Interest in our crane concept was very strong throughout the entire construction period,” says Ralph Stump. “Numerous experts and representative of renowned construction companies, planners, and engineers – many from abroad as well – visited the construction site and were impressed by our red giants in operation. We are already exploring potential follow-up projects.”
