A Digital Automating Coupling (DAC) test is currently ongoing at a test facility in Germany. The “FP5-DACtiVate” project has sought to enable the pre-commissioning of pilot trains with DAC and to conduct necessary safety tests.
The EU-funded test has brought together 21 partners, among which are operators, unions, SMEs and researchers. FP5-DACtiVate project activities include testing DAC component interchangeability, expanding wagon onboard units and validating pre-deployment trains with hybrid couplers. The tests should help ensure confidence in DAC implementation and support the authorisation process.
In June and July 2025, the test focused on derailment safety. “Several wagons connected by DACs were repeatedly pushed with increasing force into a loaded and braked line of wagons on a curved track (S-curve), which is considered particularly critical for so-called climbing effects”, writes TÜV SÜD, the owner of the test facility. Couplers of four suppliers and project partners Dellner, Knorr-Bremse, Voith and Wabtec were tested.
“The DACs were mounted centrally in the wagon line on an unloaded wagon and had to withstand a maximum horizontal compressive force of 550 kilonewtons (kN) per test. The aim was to simulate a realistic, derailment-prone scenario without an actual derailment occurring. DACs from different manufacturers were tested in various combinations to verify their respective safety and interoperability.”
Not yet included in TSIs
TÜV SÜD says that the testing results will be part of technical documentation required for the potential approval of the Digital Automatic Couplers. “So far, the DAC has not been included in the Technical Specifications for Interoperability (TSI)”, commented Dr. Stefan Soltysiak, site manager at TÜV SÜD Rail GmbH. “For this reason, railway operators currently still have to conduct their own risk assessments for DAC deployment.”
The used test facility is ideal for the DAC tests, writes TÜV SÜD. It has an area of approximately 50,000 square metres, special track formations and test benches for rail vehicle tests and tests for individual components. For the current DAC test runs, a 200-metre stretch of existing tracks was completely renewed.
“This was important for the tests with long train carriage sequences and high forces, where longitudinal compressive forces of up to 550 kN can occur – more than twice the usual”, explained Felix Bührdel, senior test engineer at TÜV SÜD Rail.