Digital Automatic Coupling Declared Ready After a €30 Million Programme
Six years of testing across marshalling yards, cross-border routes and ferry services concluded on 2 June, and the coupler carries a train-length power and data bus.
The DAC4EU research project was formally completed on 2 June 2026, with results presented at a conference at the Lippstadt headquarters of Westfälische Landes-Eisenbahn. The project ran from 2020 and received €30 million in funding from the German Federal Ministry of Transport. Consortium members included Deutsche Bahn, DB Cargo, SBB Cargo, Rail Cargo Austria, Ermewa, GATX Rail Europe and VTG Rail Europe.
Multiple digital automatic coupling variants were tested under typical operating conditions — marshalling yard shunting, cross-border routes and ferry services. The consortium and the ministry concluded that DAC is no longer an experimental concept but ready for implementation in real service, with the stated next step being testing under real-world operating conditions and preparation for large-scale rollout.
The reason this matters outside rail engineering is what the coupler carries. A digital automatic coupling is not only a mechanical connection: it runs a power and data bus along the length of the train. That turns every freight wagon from a dumb asset into a powered, addressable node.
The consequences follow quickly. Brake and load sensing become continuous rather than inspected. Train composition can be determined automatically rather than from paperwork. Onboard diagnostics that until now had to run on a battery-powered standalone tracker — with all the power budgeting and duty-cycling that implies — can instead draw from the train and report in real time. An entire category of compromise designed around the absence of power on a wagon becomes unnecessary.
For anyone in telematics the thing to watch now is the wagon bus specification and the retrofit tooling market, because the migration covers hundreds of thousands of European wagons and the wagons will be converted over years rather than at once. That means a long period in which fleets are mixed, and systems will have to handle a wagon that is powered and addressable next to one that is still a battery-powered tracker on a steel box.
Source: Railway News