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Voith Digital Automatic Coupler (DAC)

Enter the digital future of rail freight

The digital automatic coupler (DAC) is set to revolutionize rail freight with automatic connection and disconnection of air pipes, data lines, and power lines.
Its futuristic functions promise to make rail freight much faster, safer, and more efficient, all while contributing to the reduced emissions targeted by the European Green Deal. Simply put, the DAC sets an entirely new benchmark that is essential to the future success of rail freight systems.

Offering a stable data link via its integrated e-coupler, Voith’s CargoFlex powers full-scale freight digitization. With a team of uniquely experienced experts and a range of tailored services, Voith is here to help take your rail freight operations to the next level.

Basic package

Basic package including digital train functions:

  • Mechanical coupling, plus automatic coupling of e-coupler for data transfer
  • Train composition: wagon length and position detection at all times
  • Automatic brake test shortens time-consuming pre-departure process
  • Mechanical uncoupling for greater safety of staff
  • Electrical uncoupling triggered from comfort of driver’s cab

Market-leading product portfolio

    Scharfenberg® couplers have delivered reliable service in passenger rail for more than 100 years. Based on this proven technology, Voith’s digital automatic couplers introduce automatic coupling of freight trains to Europe. They are also packed with groundbreaking digital features that turn each freight train into an intelligent system.

    Market-leading product portfolio

    With more goods needing to be transported faster and on time, Voith’s CargoFlex is the key to digital, intelligent, and connected rail freight. Its integrated e-coupler helps you start your journey sooner and operate longer trains with extra functions and fewer personnel.

    Unlock the full potential of digital freight with CargoFlex.

    Coupler front part

    The front part of the coupler establishes the mechanical connection to the counter-coupler. Housing the brake pipe connection and the e-coupler, it enables consistent interoperability with other manufacturers and interfaces. It also supports marshaling hump operation and coupling with otherwise incompatible e-couplers (by keeping its own e-coupler retracted).


    The spring-loaded support holds the coupler in its vertical position and integrates a centering functionality.


    The draftgear establishes the connection to the wagon underframe. It also incorporates the coupler’s reversible and irreversible energy absorption features, with the latter enabling shunting over a hump. The integrated stabilizing linkage reduces the risk of derailment while ensuring proper starting of longer and heavier trains.

    CargoFlex Hybrid
    Operators looking to convert gradually to the DAC should opt for the CargoFlex Hybrid for locomotives. By allowing the head to be moved to the automatic and manual position as required, it enables draw hook coupling and automatic coupling alike.

    Upgrade to the DAC at your own pace with CargoFlex Hybrid.

    The e-coupler establishes permanent communication from the front to the rear of the train, enabling constant train monitoring (meets ETCS Level 3). Remote digital operation requires fewer personnel, boosts on-site safety, and keeps data secure. As the e-coupler is retracted into the CargoFlex, coupling can be performed at up to 12 km/h.

    Functional princible

    The e-coupler inside the DAC is what forms the digital connection. To keep its contacts safe, it remains retracted during mechanical coupling.

    • Cam controls e-coupler movement
    • Flap stops unauthorized opening
    • Improved safety, reduced wear

    VT Automatic Brake Testing 22 KL

    Coupling speed

    DAC must handle 16 km/h coupling speed and 100+ G accelerating forces. Voith e-coupler is not extended until mechanical coupling complete.

    • Coupler front plates absorb impact
    • Consistent e-coupler moving speed
    • Zero damage risk for e-coupler

    VT Automatic Brake Testing 22 KL

    Train functions
    The DAC introduces automated coupling to European rail freight and provides world-first digital functions. These boost productivity at every stage, offering entirely new options that get the job done faster – and more efficiently.

    Mechanical coupling

    Voith’s CargoFlex performs fully mechanical coupling. It also supports a large number of new digital functions via the automated coupling of the brake lines and e-couplers. The fast and safe transfer of data is thereby ensured throughout the train, as is a continuous supply of energy.

    Train composition detection

    This system detects the length and position of every wagon. It then sends this information to the locomotive, meaning that the driver knows the exact length of the train at all times. This is a prerequisite for the targeted one-person operation of individual couplers on the train.

    Automatic brake test

    The train is prepared to leave in minutes, with test results immediately visualized on the display. Automation boosts safety and efficiency: It guarantees safe transport of goods, enables faster round trips, and requires fewer personnel. We provide automatic brake tests and additional train functions in cooperation with our partner PJM.

    VT Automatic Brake Testing 22 KL

    Manual uncoupling

    The CargoFlex supports mechanical uncoupling, which is triggered using an uncoupling device located on the side of the wagon. This allows for easy separation of the individual couplers and represents a considerable upgrade on traditional manual uncoupling.

    Manual uncoupling
    DAC 4.5
    DAC 5

    Automatic uncoupling

    The CargoFlex enables electrical uncoupling via a button positioned on the side of the wagon or in the driver’s cab of the locomotive. This is much more effective than conventional manual methods, as it makes it simple to separate individual couplers.

    Prevent coupling

    Coupling process is prevented, e-coupler stays retracted with safety lid closed.

    • Contacts are safe from environment
    • Less wear on contacts
    • Less wear on e-coupler mechanism

    Before installing the DAC on your fleet, you must first check its compatibility with the UIC 530-1 installation space requirements. Voith offers expert support ranging from drawings and 3D data to on-site inspection of all freight wagons. Our Center of Competence for locomotives provides dedicated feasibility checks and tailored solutions for all locomotive types.


    Unrivaled real-world experience

      The CargoFlex has already been in regular service for over half a decade. Unmatched by any other solution, these years of experience stem from Voith’s pioneering partnership with leading Swiss freight transporter SBB Cargo.

      Having installed Voith’s CargoFlex on 200-plus freight wagons and 25 locomotives, SBB Cargo now plans to add it to all intermodal combined freight trains – and enjoys 50% faster formation.

      Both partners are also part of the DAC+ consortium that intensively tests the digital functionalities of the DAC on a dedicated pilot train equipped with CargoFlex.

      Logo SBB Cargo
      saw the launch of this pioneering partnership
      freight wagons now operated with CargoFlex
      faster train formation achieved by SBB Cargo
      SBB Cargo

      Benefits of the DAC

        Your guide to the DAC revolution: goodbye manual coupling, hello digitization and automation!
        Find out what this means for freight operators everywhere.

        Destination DAC: contact Voith now

          The digital automatic coupler is here – and Voith is with you every step of the way. From on-site support during migration analysis to exploring new possibilities with digital coupling, our experienced experts will help make your DAC transition a success.

          Join the future of rail freight today.

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