Digital automatic coupling


Digital automatic coupling is a type of railway coupling developed in the 2020s to replace buffers and chain couplers, initially in Europe.
It resembles the Scharfenberg coupler with extra contacts to join electrical circuits and air hoses.
The DAC project is backed by Europe's Rail, a body of the European Union. The system is among several innovations being developed within European working groups to harmonize the rail network and aims to boost freight traffic by 2030.
Although not a member of the European Union, Switzerland is associated with the project and wants to subsidize the transition to digital automatic coupling on its territory.

Advantages

Automatic couplers are categorized into five different levels in general.
  • no automation
  • Level 1: automated mechanic coupling
  • Level 2: Level 1 plus automatic coupling of air pipes
  • Level 3: Level 2 plus automatic coupling of power cables
  • Level 4: Level 3 plus automatic coupling of data cables
  • Level 5: Level 4 plus remote automatic uncoupling
For the DAC the function levels are narrowed down to specific functions. The function level DAK-3 must connect the electronically controlled pneumatic brakes. The function level DAK-4 must connect the e-coupler including electric supply and digital sockets. The function level DAK-5 must allow for [|remote uncoupling] using an electric motor. Rollout plans may use function level DAK-4 when prepared for an update to DAK-5.

Safe remote uncoupling

In addition to uncoupling from the driver's cab, the DAC must also enable uncoupling while moving on the shunting hump. In addition to a mechanical device using a cable pull/uncoupling lever, the demonstrator also had an electrical device with switches on a control panel attached to the side of the car. Further development should enable electrical uncoupling both from the train and from a tablet or hump computer. This is essentially software development with high safety requirements.

Other systems

Couplings based on AAR and SA3 already have automated mechanical couplings, so some of the advantageous features of DAC are lessened. These have a maximum draw gear load well in excess of that possible with the DAC, say 1800 m instead of 750 m.

Makers