Digitale Kupplung

 Digital and automatic

Modern coupling technology in the rail freight sector is both digital and automatic. Commissioned by the German Federal Ministry of Transport and Digital Infrastructure (BMVI), a pilot project to demonstrate, test and approve the use of digital automatic coupling (DAC) in freight trains started in June, and trials are now in full swing.

Thorough testing is currently underway in the German town of Görlitz.  These tests entail linking wagons together multiple times while varying the parameters, i.e. using different loads, speeds and track radiuses. Ulrich Meuser is the project manager for the pilot. "The project is running completely to schedule", says Meuser. "To see if the couplings work properly, we need to conduct extensive tests under real-world conditions. We've already clearly shown that DAC makes the work of forming freight trains much faster, which in turn considerably boosts on-track capacity." This means DAC can make a real contribution to ensuring that the decarbonisation of transport is a success. In addition, the new technology reduces the amount of manual labour rail employees need to perform since DAC eliminates screw couplings, which have to be connected by hand. This manual coupling system has been virtually the only system used in rail freight operations throughout Europe for over 100 years. Using screw couplings, wagons have to be hitched and unhitched completely by hand. First, a shackle weighing some 20 kg is connected to the hook of the adjacent wagon.

Schraubenkupplungen per Hand
Manual screw coupling

The coupler is then tightened by adjusting a turnbuckle-style screw behind the shackle. In contrast, DAC automatically connects adjacent freight wagons. In this way, the system creates a mechanical tie between the wagons, and shunting staff do not need to perform any manual work. Every day, DB Cargo alone links up some 54,000 wagons in Germany. Counting all of Europe, the daily figure comes to about 400,000 wagon couplings in rail freight operations.

Digital automatic coupling will boost single wagon transport

The pilot project's testing process uses twelve freight wagons fitted with couplers from four different manufacturers. Once the trials are over, a European committee will select one DAC system. Then, a test train with 24 wagons fitted with the selected DAC solution will spend several months travelling throughout Germany, Austria, Switzerland and other EU countries. This will provide an opportunity to evaluate DAC from different angles, such as its day-to-day use at marshalling yards, which could see their capacity increase by up to 40%. Ultimately, DAC will be one of the keys to increasing volume in rail freight transport by some 70% or more.

A new era for rail freight transport

In the past, several attempts have been made to introduce a Europe-wide automatic coupler, most recently in the 1990s. These attempts focused on a purely mechanical coupler linked with air pipes, but this approach was not sufficiently cost-effective. In contrast, DAC offers a much wider range of uses by including power and data connections as well. The new system will facilitate the wide-ranging digitalisation of rail freight transport, making its benefits and potential far greater than what previous solutions offered.

Digitale Kupplung
Digital automatic coupling

Running until the end of 2022, the research project was commissioned by BMVI, which has also provided funding to the tune of EUR 13 million. The project also involves a consortium of six companies: alongside DB and its subsidiary DB Cargo, they are Swiss and Austrian freight operating companies SBB Cargo and Rail Cargo Austria, plus wagon keepers Ermewa, GATX Rail Europe and VTG. Within DB, the venture operates as an integrated rail project that is jointly managed by DB AG and DB Cargo as part of the Technical Excellence Group programme, or TecEX for short.

The outlook for launching a Europe-wide DAC system was never as good as it is now. As the roll-out process can take six to eight years to complete, the system is slated to start in 2023/2024 at the latest so that it is largely done by 2030. According to a BMVI-commissioned study, the roll-out will be a gargantuan task, requiring the refitting of up to 490,000 freight wagons and 17,000 locomotives in the EU's 27 member states, Switzerland, Norway and the UK.