Voith Left Waiting as DB Systemtechnik Seals EU-Rail DAC Contract

EU-Rail has selected DB Systemtechnik as the main contractor for retrofitting locomotives with Digital Automatic Couplers (DAC), while Voith and Wyss & Lila Italia were placed as secondary suppliers. The contract, worth EUR 3 million, aims to deliver technical solutions for Europe’s long-delayed DAC programme.

The joint EU and rail industry body EU-Rail has announced the results of its tender for the technical retrofitting of locomotives with Digital Automatic Couplers (DAC). Three companies were selected: DB Systemtechnik, Voith, and Wyss & Lila Italia. The contract was awarded under a cascading model, meaning multiple suppliers were ranked in order.

The first-ranked company, DB Systemtechnik, is the official winner and has been authorised to carry out the project. Should DB Systemtechnik fail to deliver, Voith would assume responsibility, followed by Wyss & Lila Italia if required. According to EU-Rail, this method provides certainty that the contract will be completed without launching a new procedure — a safeguard considered crucial given the years of delays in the DAC project.

DAC Contract Valued at €3 Million

The procurement seeks "sufficient and complete information for the installation of a full DAC system on a given locomotive type." The solution must include the coupler itself, electronic components, data and communication systems, and a power supply unit for the entire DAC-equipped train. "The contract will also cover research, analysis, development of technical solutions, and possibly testing of a limited number of locomotive types" for DAC and ERTMS systems, the documentation states. The estimated value is EUR 3 million with a duration of 48 months.

The agreement further stipulates that the selected companies may provide similar services in the future without prior publication of a new call for tender. In practice, DB Systemtechnik will enjoy a privileged position in forthcoming DAC-related projects, potentially receiving up to 50% of the value of future contracts directly.

Testing in Germany to Boost Operator Confidence

Testing of the DAC is currently underway at a dedicated facility in Germany as part of the FP5-DACtiVate project, which is intended to prepare pilot trains for early deployment and conduct essential safety checks. The programme, funded by the EU, involves 21 partners, including operators, trade unions, SMEs, and researchers.

The project activities cover interoperability tests of DAC components, the expansion of wagon onboard units, and pre-deployment verification with hybrid couplers. The aim is to raise operator confidence in DAC implementation and accelerate approval processes. Due to funding issues, however, companies from Czechia, Slovakia, and Poland are not participating in the tests.

Stress Tests: DAC Must Withstand Extreme Forces

In June and July 2025, testing focused on derailment safety. "Several wagons coupled with DAC systems were repeatedly pushed with increasing force into a loaded, braked row of wagons on a curved track (S-curve), considered especially critical for climbing effects," reported TÜV SÜD, which provided the testing facilities. Couplers from four suppliers — Dellner, Knorr-Bremse, Voith, and Wabtec — were examined.

DAC couplers were mounted on an empty wagon placed in the middle of the train and subjected to a maximum horizontal pressure of 550 kilonewtons (kN) during each test. The goal was to simulate derailment-prone scenarios without causing actual derailment. The couplers from different manufacturers were tested in various combinations to verify safety and interoperability.

Testing on a 200-Metre Track

TÜV SÜD, based in Görlitz, Saxony, stated that the test results will feed into the technical documentation required for DAC approval. "The Digital Automatic Coupler does not yet have Technical Specifications for Interoperability (TSI)," commented Dr. Stefan Soltysiak, Head of TÜV SÜD Rail GmbH. "For this reason, railway operators must conduct their own risk assessments during DAC deployment testing," he added.

The testing facility spans 50,000 square metres and includes special track layouts, test benches for rail vehicles, and facilities for component testing. For DAC trials, a 200-metre section of track was fully rebuilt to allow experiments with long train formations under longitudinal forces of up to 550 kN — twice the usual level, explained Felix Bührdel, lead test engineer at TÜV SÜD Rail.

Sources: EU-Rail; TÜV Süd