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Exclusive Information from DAC4EU Testing. How Does the Automatic Coupling Perform in Operation?

Exclusive Information from DAC4EU Testing. How Does the Automatic Coupling Perform in Operation?
foto: Archive/Exclusive Information from DAC4EU Testing. How Does the Automatic Coupling Perform in Operation?
05 / 12 / 2022

This week saw the long-awaited presentation of the project of the German Federal Ministry of Transport and Digital Infrastructure and the DAC4EU consortium on the results of the testing of the digital automatic coupler. The testing project was funded by the German Ministry with EUR 13 million and was timed from June 2020 to the end of 2022. The DAC4EU consortium consists of a narrower and different group of partners than the one formed by the European Railways Joint Undertaking (ER JU) and the EDDP - European Digital Coupling Programme, namely DB, Ermewa, GATX, SBB, CFF, FFS Cargo, Rail Cargo Group and VTG.

The video presentation and seminar were organized by DB and its introduction was along the lines of highlighting the benefits of DAC by highlighting the savings in train building, train marshaling, infrastructure capacity, and the possibilities to use longer, faster, more flexible, and heavier trainsets. DAC must guarantee safety and absolute reliability. DB's Fabian Wartzek pointed out that there has never been a comparable test operation in history. Through testing we must arrive at a product that is not only ripe for use but also for 'industrialization', in other words, a complex technological product with digital support must be created that is ripe for the market. As input to the testing, a preliminary market analysis with the participation of 4 manufacturers was carried out, from which Voith's Scharfenberg product came out best. The testing consortium decided to extend the originally foreseen end of testing to December 2022, in other words, the testing is far from over, as the tests revealed the need to further refine the technical solutions. It was clear from the presentation that the testing group is working under political pressure from the DAC4EU project management, as it is clear that without satisfactory and definitive testing results, the standardization of the product cannot proceed. Testing will be extended until mid-2024, with a request or announcement of interest in 1Q 2023 for testing in certain conditions in EU Member States and EU-associated countries. DB Structure's DAC project manager Fabian Wartzek gave an overview of how the testing has progressed so far. A total of 200 individual tests and 200 tests in artificial climatic situations have been carried out in a temperature range of -25 to +40 degrees, with permanent snow cover on parked trains and in other simulated (climate chambers) or real conditions on various types of wagons. Testing included 25 locations in 7 countries, including the Czech Republic. Tests in Luxembourg and France are scheduled for the end of this year. On the other hand, tests on locomotives have not yet started at all. The reason for this was their scarcity and, as DB admitted, also the lack of clarity on the technical design of the DAC on each type. Mechanical, electronic, and digital DAC components were tested. In particular, the parameters of electrical power in the DAC train set, data and communication, braking systems, individual shifting situations, and car shifting were tested. Daniel Jobstfinke, the project leader of the testing group from DB System Technik, then presented the specific conditions and situations that his team had prepared for the testing in Germany. In cooperation with Switzerland, they tested the border sorting of DAC cars into individual trainsets. Next, representatives of the Swiss and Austrian Cargoes from the testing consortium spoke about the specifics and results of testing in the Alpine environment under winter conditions. In addition, Switzerland provided the project with data from the 2019 DAC testing and highlighted its adaptability to the climbs and extreme winter conditions in the Gothard Pass. Next, PKP Cargo representative Tomasz Rozynek took the floor. The testing in Poland took place over ten days in July 2022 and T. Rozynek presented a much more critical assessment than the consortium members. He stated that they had subjected the DAC in Poland to testing in coal thawing halls at the power plant sites, while the robustness of the digital and electrical heating installation is unclear and will require further testing. On the other hand, he positively evaluated the robustness of the DAC parameters during the rotation of wagons, which is carried out to discharge coal at the premises of power plants. The current DAC performed poorly in dust resistance in these coal plants and especially failed in cement plants. The Polish conclusion is that the DAC needs technical improvement when handling bulky materials, which has been acknowledged by the organizing DB and, according to PKP Cargo in Poland, there are also potential safety problems with the uninsulated end of the DAC disconnector, which is, however, energized at some stage. In terms of contamination, there is a problem with dust contamination of the brake hoses. He confirmed that he is looking into the problem. The Polish representative also suggested one sub-improvement - the batteries to power the DAC have no visible led indicator for the voltage level. Later in the workshop, the attitude of the workers who were familiar with the DAC was discussed, and despite preliminary caution and skepticism, they were ultimately positively enthusiastic about the result. However, there are subjective complaints about higher noise pollution. The test group could not objectify the noise load because they did not investigate it. It will therefore also measure noise in the future, although DB stated directly at the workshop that the testing is more vigorous and therefore noisier than future standard operation. It also admitted that it will look at better ergonomics of the controls, which have been criticized by railway staff in various countries.

Testing of the electrical installation and digital components was presented by DB's Florian Einsele. Statistical analysis of power interruptions and digital component failures is being carried out, but these were limited in testing to units or sub-tens of milliseconds. The evaluation of the external influences that cause the outages goes to the account of vibrations and this is how the team deals with them. The reliability of the wi-fi support of the DAC is still very questionable, everything will be more towards gateway/ethernet and cable/connector interconnection.

Testing the reliability, robustness, and interoperability of DAC is proving to be a key element in the DAC deployment roadmap. Without a final reliability result, it will not be possible to implement TSI changes. Further testing of the nodes may bring the need for some technological improvements. A fundamental change to the DAC deployment process may come from locomotive testing. Ultimately, the overall schedule, the cost of digital automatic coupling, and the overall cost of the transition may undergo significant changes.