DIGITALISATION and automation are making rail freight intelligent. At present, processes are largely manual. This affects many different areas. For example, employees manually check each individual brake before every train departure. Coupling trains is also a tough physical job which has to be done outside, whatever the weather. And once the journey is underway, the locomotive crew is partly blind: for example, from the cab, there is no way to check whether the train is still complete. Such activities contribute to the current staff shortage, as this career profile has long been outdated. Moreover, the modernisation of rail freight is lagging behind in comparison with road transport. It is therefore high time to move rail freight forward and thereby increase its appeal to the market.

To this end, and with the support of the Swiss Federal Office of Transport (FOT), an international consortium consisting of SBB Cargo, Lucerne University of Applied Sciences and Arts (HSLU), and the companies PJM, PLC-Tec and Voith set up a pilot project a year ago to promote automation and digitalisation in rail freight, resulting in single-person operation, among other outcomes. The centrepiece is the recently launched DAC+ digital pilot train.

Voith’s CargoFlex automatic coupler, with its mechanical pneumatic connection, has already been in commercial use at SBB Cargo for more than three years. Now the focus is on the digital automatic coupling (DAC), providing additional power and data connectivity along the entire train.

At the European level, the development and introduction of the DAC is being driven forward by several initiatives and development projects. The lead organisations are the Europe’s Rail Joint Undertaking (ERJU), the European DAC Delivery Programme (EDDP) and the DAC4EU consortium. National initiatives are just as important to the success of the project, and projects are currently underway in several countries to test and further develop DAC.

The results of the project will feed into the further development of the DAC at the European level.

The decision to opt for a uniform type of coupler head was made by the EDDP in autumn 2021. SBB Cargo has done pioneering work, contributing significantly to this development: in previous years, and together with Voith, the company has tested and further developed the selected Scharfenberg coupler head, and is the only operator in Europe to have already put it into operation. The first wagons were converted in 2019. This is an example of how experience gained at SBB Cargo is incorporated into European specifications, norms and standards.

The task at the European level is now to define the technology for data transfer.

Data transfer

There are currently various technologies for energy and data coupling. The solutions, the system architecture of the train, and the subsystems in the DAC+ project are based on the previous results of the EDDP and the DAC4EU consortium, as well as on SBB Cargo’s preliminary work on automatic coupling and its implementation.

The pilot train is equipped with the digital automatic coupler and additional power and data connections.

One of these technologies is the Powerline PLUS Train Backbone (PTB) data link, which connects all wagons and the locomotive via the DAC. Powerline Plus is a wired communication technology developed by PLC-Tec and its research partner HSLU. The main advantage is that the data is transmitted along the power cables and plugs, so that no additional data cables, electrical contacts or plugs are required.

The second technology is Single Pair Ethernet (SPE), which transmits the data via separate data lines and additional electrical contacts in the DAC instead of the power lines. An SPE solution optimised for freight trains is currently still under development. As soon as such a solution becomes available, the two technologies will be compared against various criteria in a specific test programme.

The automated freight train

The digital data line in the DAC enables the implementation of various automatic applications in a freight train. Once the digital connection between the wagons has been established and if the wagons are equipped with the appropriate electronic systems, a number of functions can be undertaken, for example:

  • automatic detection of the wagon order and the orientation of the individual wagons
  • automatic brake testing
  • data and communication services, including the monitoring of train integrity when in motion
  • intelligent energy management
  • electro-pneumatic braking
  • remote-controlled uncoupling of the wagons from the locomotive, and
  • condition-based and predictive maintenance.

Such automated or remote-controlled train functions contribute significantly to process optimisation and thus to saving time. They also enable greater efficiency in marshalling and operating freight trains.

The pilot train consists of six container wagons and one covered wagon.

The test programme

The test programme with the DAC+ pilot train includes static tests of the train, train operation and shunting. The pilot train consists of six container wagons, which function as test wagons, and a covered wagon acting as a simulated locomotive, integrating the power supply and the test and measurement equipment for the other wagons.

This train is used to test the automatic applications mentioned above, with the exception of the electro-pneumatic braking system.

The tests will take place at various locations, as well as on test runs throughout Switzerland, until the end of 2023. The results of the project will flow into the further development of the DAC at European level. The pilot train is thus making an important contribution to the future of rail freight and to the introduction of the DAC across Europe because, in principle, the growing volume of freight can be handled sustainably by rail - providing that rail freight is modernised. This opportunity needs to be taken advantage of now.

* Stefanie Probst is communications specialist and Anja-Maria Sonntag head of development asset management with SBB Cargo, while Ulrich Dersch is director of PLC-Tec.