Comark Steers Project Success Along the Danube

By Simon West

Comark has showcased its expertise in heavy cargo logistics by successfully delivering a 200-ton rotor for Siemens from Slovenia to Germany, following a complex transport route via Croatia’s Port of Vukovar and along the Danube River. We caught up with Klemen Butala, project manager at Comark, to find out more about this impressive cross-Europe project.

From Issue 2, 2025 of Breakbulk Magazine

Q: Can you break down the exact route taken from Slovenia to Germany?

PB: The rotor’s journey began in Slovenia, where it was loaded onto a 20-axle modular truck trailer. From there, it traveled by road through Slovenia and Croatia, reaching the Port of Vukovar. At Vukovar, the rotor was transferred onto a barge vessel, which navigated the Danube River toward Germany. The final unloading point was located along a river canal in Mülheim an der Ruhr, Germany, where the cargo was offloaded at the client’s facility.

Q: What factors influenced the decision to route the shipment through the Port of Vukovar in Croatia?

PB: The transport of a 200-ton rotor is restricted by some road infrastructure limitations in Slovenia, Austria and Germany. The total weight of the cargo and transport composition exceeded the permissible road transport conditions in these countries, making a full road solution impractical and uneconomical. Such a move would have resulted in excessive transport costs, permit fees, escort requirements, and necessary infrastructure reinforcements. Given these constraints, the only viable alternative was to move the cargo via a multimodal approach combining road and river transport. The Port of Vukovar was chosen because it provided a direct link to the Danube River, allowing for efficient waterway transport directly to customer, where the final unloading site was situated along the river. Additionally, by shifting a major portion of the transport to waterways, Comark was able to bypass numerous road transport restrictions and significantly optimize costs and logistics.

Q: What kind of specialized equipment was used to lift and move the rotor?

PB: The handling of the 200-ton rotor required highly specialized equipment, including a gantry crane used at the origin site to lift and position the rotor onto the truck, a 20-axle modular truck trailer designed to distribute weight evenly and allow safe road transport, and a barge vessel, selected to handle extreme loads for river transport. Since Vukovar did not have cranes with sufficient lifting capacity, Comark organized lifting equipment at the port specifically for this operation, including a 500-ton heavy-duty mobile crane. This additional set-up ensured a safe and efficient cargo transfer from truck onto the barge.

Q: Were any modifications made to existing infrastructure (ports, roads, or bridges) to accommodate the transport?

PB: Yes, some temporary changes were made along the road route to make it easier for the cargo to pass. Before starting, we did a detailed route survey and identified areas that needed adjustments. This included moving overhead cables, temporarily removing traffic lights and signs, and making changes to roundabouts and urban areas for more space. Luckily, no changes to bridges were needed because all the bridges on the route could handle the load.

Q: What were the biggest logistical challenges faced during this transport?

PB: One of the most complex aspects of the project was the coordination of multiple operations, which had to align precisely to avoid delays. The biggest challenges included synchronizing all key stages, as the operation required close coordination between different phases, including hydraulic lifting at the loading site, transport, crane assembly in Vukovar, and barge loading. Another challenge was the barge schedule and river navigability. The Danube River’s water levels fluctuate significantly, especially in summer months when drought conditions can impact navigability. Transport had to be carefully timed to ensure the barge could navigate the full route without delays. Finally, we had to manage multiple contractors. The project involved multiple service providers, including transport teams, crane operators, port personnel, and barge crews. Ensuring all schedules aligned was critical to keeping the project on track.

Q: How long did the entire journey take, from departure to final delivery?

PB: The entire journey, from departure in Slovenia to final delivery in Mülheim an der Ruhr, Germany, took about three weeks. The transport required meticulous coordination between road and river transport, with careful planning to align with barge schedules and river navigability conditions. The duration also included necessary preparations such as crane assembly at the Port of Vukovar and temporary road modifications to facilitate smooth passage.

Q: Was there a particular moment or aspect of this project that you found particularly rewarding?

PB: The most rewarding aspect of this project was seeing months of planning come together seamlessly, from precise engineering calculations to the flawless transition between transport modes. The successful execution of this transport not only showcased Comark’s technical expertise but also reinforced the value of strategic planning and collaboration in the field of heavy and oversized cargo logistics.

Comark will be exhibiting at Breakbulk Europe on 13-15 May in Rotterdam.

Top photo: The rotor is loaded into the barge for journey along the Danube. Credit: Comark
Second: Klemen Butala, project manager at Comark. Credit: Comark