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Efficient and Economical


Many trains, not owned by the German Railway System, are currently adding a significant manual expense to the operation and maintenance of their infrastructure and auxiliary services. Not, however, those run by AKN Eisenbahn AG. Based on WAGO’s decentralized automation technology, the company from Kaltenkirchen has developed a system that is as creative as it is economical: Approximately 4,000 fault messages can be centrally monitored from the control center, and remote control functions can also be carried out in many areas.

In the Hamburg metropolitan region, traffic chaos is the daily norm. Local public transportation is taking on an increasingly important role. With 39 stations on 95 km of tracks, AKN Eisenbahn AG offers a high level of mobility between Hamburg and southern Schleswig-Holstein. In addition, AKN’s infrastructure includes a central signal tower with depot, 118 public railroad crossings, 277 signal lights, 108 points, and the only tunnel in Schleswig-Holstein. Like many non-federal railways, AKN competes for passengers and haulage. Customer safety and comfort are the highest priority. At the same time, the company from Kaltenkirchen is constantly looking for opportunities in order to operate and maintain their complex infrastructure more efficiently – to remain economical over the long term.

WAGO-I/O-SYSTEM 750: Modular, Compact and Economical

“The functionality of our previous technology was severely limited,” according to Kay Petermann from the Signaling and Telecommunications Department. “We were looking for a flexible system that was easily expandable and cost efficient, and which we could use for all of our auxiliary services.” The 750 Series I/O System from WAGO, located in Minden, caught their eye. As a decentralized automation solution that supports all conventional fieldbus protocols and ETHERNET standards, it offered the possibility for positioning intelligent control units at the strategically most important points within the AKN infrastructure. At these locations, the WAGO units, consisting of controllers and I/O modules, tap the relevant data and inform the technicians and the dispatcher about faults in the AKN operating region. The messages can be distributed directly to the mobile telephones of the employees responsible, and the control center in the signal tower (dispatch) takes over coordination of the necessary measures.

Central Fault Data Determination for the Auxiliary Services

The first application in which AKN used the 750 Series was for point heating: Frozen points can lead to delayed trains in winter. In this case, a fault in the supply network causes an outage in the point heating. The challenge is to recognize when the network has restabilized and the heat can be switched on again. In the past, this had to be checked on site, at significant expense in personnel and time. Today, the WAGO-I/O-SYSTEM recognizes the power failure and automatically switches the point heating back on as soon as the network has run stably for 10 s. In addition, the dispatcher can manually trigger a short-term heating in order to heat the points during extreme temperatures as a precautionary measure. “Proceeding from this successful application, we linked several additional functions from our auxiliary services into the fault data determination,” explains the telecommunications expert. “They all involve the same principle and the same controls. This was very advantageous for us, in replacement parts management as well. We were additionally convinced when the solution took up only one-tenth of the installation space as our old technology.” The approximately 50 decentrally distributed WAGO controllers communicate via the MODBUS protocol and are linked via TCP/IP to a central OPC server in the electronic signal box (ESTW), where the data converge.

Creative Applications from Ticketing Automats up to the Tunnel

The temperature of the ticketing automats was monitored in the same way, as they are exposed to extremes of weather on the station platforms. Conventional timer switches, used for lighting in the train stations and exterior areas, were replaced. And on Fehmarn Island, whose train station is around 150 km away from Kaltenkirchen, AKN operates a system using the 750 Series that monitors the ground fault interrupter for the mains supply and, if this is triggered, can switched it on again using a motor; in this way, the maintenance trip, which used to take an entire day for this task, has been eliminated. The railway operators use the technology from Minden’s family company in their Ulzburg tunnel in order to monitor the travel time of trains as they pass through. If delays or an emergency stop occur during passage, the I/O system recognizes the unscheduled stop, switches the lighting on for safety, and notifies central about the fault.

Fifty Controllers for around 4,000 Fault Messages – the Tendency is Increasing

“We have been positively surprised by which functions we could quickly and economically link into the automated fault indication system using WAGO’s technology. In spite of that, we have a lot of additional ideas for the future,” notes Kay Petermann. In addition to the examples mentioned, elevators, emergency diesel generators, doors in the control center, level gauges in the storm water detention reservoirs, cameras at train crossings, and lightening protection modules are also monitored, to which was recently added the parameters in their combined heat and power unit. This versatile and comprehensive usage is possible because the I/O system allowed Kay Petermann and his team to give full rein to their creativity, and they could always expand the existing system in a modular fashion.

Text: Marco Schrader, WAGO
Photo: Fabian Schindler/, WAGO