Top tech in the tunnel

The Ceneri Base Tunnel connects the northern and southern parts of the Swiss Canton of Ticino and serves as the southern approach to the Gotthard Base Tunnel. Yet the tunnel, which opened in September 2020, is more than just a 3.6 billion Swiss franc investment in international rail infrastructure. It also cuts the commute between Locarno and Lugano from 55 to just 22 minutes.

In any given hour, as many as ten trains – four freight and six passenger – pass through the tunnel in each direction. With this tight schedule, reliable operation has top priority. The performance of every system and every component is crucial to ensuring the passengers and cargo reach their destinations not only safely, but on time.

Achieving and maintaining this operational reliability is no simple task. "Control and monitoring of the 50 Hz systems requires 30,000 hardware and communication data points," says Harald Störk, Managing Director of Leicom AG. The systems integrator from Winterthur integrated all medium-voltage systems with transformers and no-break systems as well as escape route signaling, track field lighting and more.

Such an enormous number of data points is more than any one controller alone can handle. In the 15.4-kilometer-long Ceneri Base Tunnel, the job is done by 104 controllers from B&R's X20 series. In each of the crosscuts that connect the two tunnel tubes every 350 meters, two X20 controllers control and monitor rail traffic – one for each direction.

How do you keep track of so many data points? "To properly handle a project like this, you need an engineering tool that reliably manages not just five, but 104 controllers," says Störk. As a B&R integrator, he knew B&R's APROL process control system was the obvious choice for the job. He had already used APROL in other SBB projects, for example to integrate and manage large stations such as Zurich in a higher-level control system.

Despite this familiar technology, the project held some challenges. "We had to incorporate the X20 controllers into a higher-level, redundant control system from another manufacturer," says Störk. The OPC UA interface that comes standard on all B&R controllers made this considerably easier. Another sticking point proved to be the large number of standard and proprietary protocols that had to be used to connect the third-party systems to the X20 controllers. But this hurdle was also overcome with the support of B&R.

How big of a role does B&R play in the operational reliability of the Ceneri Base Tunnel? "A very big one. The high reliability, the stability and the quality of the hardware speak for the X20 controllers," assures Störk, adding: "The system's running smoothly. Since project completion in August 2020, we have had virtually no service calls. Given the number of data points, that's extraordinary."