https://www.witron.de/en/ The stacker crane in the central warehouse of SPAR in St. Pölten in Austria has been in service for 17 years. Now, it was time for a retrofit, a modernization. However, the task was quite difficult: the only possible access was a 3 x 5 m small roof opening. A 500-ton assembly crane with a working height of 145 m was erected in order to move the old stacker crane out of the warehouse from a distance of 120 m and install the new one. A difficult process for all parties involved. Good preparation work was required due to a tight time schedule and many basic conditions had to fit. WITRON mastered the challenge as the general contractor.