DAC demonstration train used to test digital automatic coupling in rail freight.

DAC demo train: a closer look

DAC Tales

In 2026, the ÖBB DAC demo train will embark on a grand tour across Austria, facing a wide range of challenging situations from everyday freight transport. Read on to find out how the train is configured and which aspects are given special attention during testing.

The DAC demo train: as diverse as freight transport itself 

Initially, the DAC demo train consists of eight wagons, expanding to 24 wagons from mid-2026 onward. These include wagons of the types Eanos, Sgnss, Shimmns (4668 & 4676), Habbiins, Talns and Faccns, as well as two Vectron locomotives. The variety of wagons allows for testing numerous train configurations, as commonly found in single wagonload transport. Additionally, the DAC demo train gathers empirical data for double traction, which is used for very heavy trains or challenging gradients.

Habbiins freight wagon marked for DAC testing standing on railway tracks. At over 20 metres long, Habbiins wagons are among the longest in the DAC demo train. They are used, among other things, to transport palletised goods.

When selecting the wagons, care was taken to ensure that the rolling stock is both widely-used and future-proof. This means that instead of two-axle wagons, only modern bogie wagons with a higher payload capacity are used.

Talns freight wagon marked for DAC testing standing on railway tracks. Short wagons such as Talns (pictured), Shimmns and Faccns accelerate faster than long wagons when leaving the marshalling hump. Combining as many different wagon types as possible provides a realistic picture of a single wagonload train and delivers valuable operational insights for the DAC demo train team – including data on the forces acting on the couplings. Relevant insights are shared as part of European research projects.

Packed with modern technology 

The most obvious changes can be found in the couplings of the demo train. It is equipped with 44 Digital Automatic Couplings (DAC) from different manufacturers, all of which are mutually compatible. Additionally, the two Vectron locomotives have four hybrid couplings, enabling them to haul wagons equipped either with DAC or conventional screw couplings.

Furthermore, each wagon is equipped with a CCU (Consist Control Unit) and each locomotive with an LCU (Lead Control Unit). These computing units are ideally installed at the former buffer positions of the wagons or within the locomotives. They provide a power supply as well as continuous communication between the locomotive and the connected wagons. For example, the wagons send a signal to the locomotive approximately once per second, informing the driver that all wagons are connected and that train integrity is ensured.

DAC demonstration freight train standing on railway tracks in a rail yard. For testing purposes, Siemens Mobility has retrofittedtwo ÖBB Vectron locomotives for the DAC demo train and equipped them with additional electrical systems and a dedicated power supply for the wagons.

Not only Austria is testing 

In addition to Austria, tests with DAC demo trains are also being carried out in four other European countries, including Germany, Italy, Sweden and Switzerland, with data and comparative values being collected. Special consideration is given to the characteristics of each country. While Austria's topography features tight curves, steep gradients, tunnels and alpine conditions, Sweden, for example, has very long stretches of track with harsh winter conditions. Thousands of train kilometres are covered on these routes, with particular attention paid to wear and tear.

The DAC demo train’s first major journey through Austria will take place on the Tauern line. Special winter tests will be carried out there in January, before the train undergoes trials at the shunting yard in Salzburg-Gnigl. First impressions from the tests as well as insights into the different DAC manufacturers will be available on the DAC Tales blog soon.

Disclaimer

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the Europe’s Rail Joint Undertaking. Neither the European Union nor the granting authority can be held responsible for them.

The project is supported by the Europe’s Rail Joint Undertaking and its members.