Rails, signal boxes, overhead lines, switches and many other structures keep the railroads in Germany on track. They have to be continuously renewed to ensure that passengers reach their destinations safely and punctually. DB Netz AG is responsible for a rail network of around 33,300 kilometers with more than 67,000 switches, which the maintenance specialists keep in good shape and thus meet quality requirements. This not only involves many routine repairs, but also spontaneous cases of damage that need to be rectified.

The Witten track materials plant ensures the supply of track materials to DB Netz AG. More than 1,300 turnouts and crossings and several thousand other large parts for turnouts are manufactured here every year and sent on their way to their place of use. All large and small components needed for switch construction and maintenance are also stored in the plant's warehouse. Warehousing is handled by an automated intralogistics system with complex conveyor technology and storage and retrieval machines (SRMs). The experts from Konecranes and Demag Services are familiar with the requirements for storage racks and modernize the storage technology comprehensively.

From partial to complete refurbishment
The many different components that are stored in the Witten racking warehouse must be reliably transported to and from their storage position. Conveyor belts bring the standardized containers and pallets to the shelves, where automatic storage and retrieval machines take over and move them to their final positions. In total, more than 30 electric motors work in the area of conveyor technology - as lifting drives, in chain conveyors and at the pallet placement station. There are also many other electrical components, from sensors to emergency stop switches. During maintenance work on the SRM units, the experts from Konecranes and Demag Services realize that the warehouse's entire intralogistics system needs to be modernized in order to meet the system's high reliability and safety requirements. "As a system ages, it becomes increasingly difficult to find replacements for many components, for example when series are discontinued," says Thorsten Minklei, Intralogistics Manager at Konecranes. "Software is also developing rapidly, with new functionalities being added and replacing older applications." The service team from Konecranes and Demag Services, which is specially qualified in accordance with DIN EN 528 for storage and retrieval machines, inspects the entire installation in detail. The result: an all-round modernization is needed - from the electrical components, some of which are heavily worn, to the machine control system.

Sustainably modernized high-bay warehouse
The intralogistics system for the racking warehouse was originally built in 2000 as part of a larger system - many of the function and safety-critical components are therefore already more than 20 years old. The aim of the comprehensive modernization is to replace all electrical components that have reached the end of their service life - they have the highest risk of failure. "The automated warehouse in Witten must continue to function perfectly in the future," emphasizes Thorsten Minklei, "which is why our service team uses state-of-the-art and proven components that will be available for at least another 12 to 15 years." The machine control system, which is more than 20 years old, will also be replaced with an S7-1500 controller with TIA Portal.
"Safety and reliability are fundamental when it comes to the operation of our racking warehouse," says Andreas Scholz, Head of Investment Planning in the area of plant technology at DB Netz AG. "We not only supply ourselves, but also many other locations with spare parts. In addition to the electrical drives and the control software, the entire safety technology therefore also needs to be modernized." In addition, the components in stock will continue to be used during the modernization - it is therefore not possible to shut down the system for an extended period of time. The Konecranes and Demag service team is working with the Witten-based railroad specialists to design a technically efficient solution - and the right timing to go with it.

From the electric motor to the laser sensor - everything is coordinated
The complete modernization is planned in detail in advance and carried out over several weekends in order to keep the warehouse as operational as possible. Many small and large assemblies are replaced and adapted, from the drive technology to wireless sensors. These ensure that the control system knows where the storage and retrieval machines are located at all times and can switch off in good time if people enter the safety zone. To ensure that all components work together smoothly and communicate with the PLC, the Profinet communication protocol is used in the modernized system. The experts also put together the control cabinets and integrated them into the warehouse.

All steps of the modernization are documented - this significantly simplifies the operation and future maintenance of the high-bay warehouse at the Witten plant. Thorsten Minklei is delighted: "With the successful completion of the refurbishment, our service team has shown that Konecranes and Demag Services are the ideal partner for all intralogistics issues - from cranes to stacker cranes." The completely new machine control system also enables the system to be integrated into Konecranes' Remote Services. "For six months after commissioning, our remote maintenance via our own network is free of charge for our customers. This means we can be reached quickly for any questions."