Digital revolution in rail transportDB Netz AG is a railway infrastructure company that operates some 87.5 percent of the German rail network. Nearly half of its 3,000 interlockings are relay interlockings installed about 70 years ago. The next generation of interlocking technology was the electronic models. As part of the Digital Rail for Germany (DSD) initiative, Siemens Mobility and DB Netz AG co-developed modern digital interlocking technology (DSTW).
In September 2019, Siemens Mobility commissioned Germany’s second digital interlocking, the first to be used in mainline service. The pilot project was implemented in Annaberg-Buchholz in 2013.
The new interlocking technology is distinguished by its IP-based architecture and standardized interfaces. DB Netz AG is now driving the conversion to the new DSTW technology in several different projects. The goal is to prepare it for series production.
In our collaborations so far, Siemens has proven to be an innovative partner and has explicitly demonstrated its experience and technical expertise.Ingo Buhlke, Project Manager, Large-scale Projects, East, at DB Netz AG
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Digital Interlocking WarnemündeGermany’s first digital interlocking in mainline service, the DSTW Warnemünde, is a pre-series project from Siemens Mobility and DB Netz AG. Following the first DSTW pilot project in Europe for the Erzgebirgsbahn in Annaberg-Buchholz, Warnemünde has now also been put into operation with the latest interlocking technology.
Flagship project Warnemünde
The reference and pilot projects, along with the associated pre-series projects, are important milestones in digitalization. As a pioneer in rail digitalization, DB Netz AG created a total of four pre-series projects in preparation for the rollout of DSTW technology. The Warnemünde pre-series project and the DSTW implemented in this context have laid the foundation for the rollout of DSTW technology in the Rostock network area.
In mid-2018, the company commissioned Siemens Mobility to replace the old relay interlocking with an interlocking of the latest generation. With 22 points and 66 signals on a nine-kilometer line, it may not be the largest project, but it’s an extremely important one for both companies.
Paradigm shift implemented seven years ago
The earlier pilot project in Annaberg-Buchholz represented a paradigm shift in the field of rail control and safety systems. The knowledge acquired contributed to the design of standardized interfaces and the development of Siemens Mobility’s DSTW.
The newly developed and approved DSTW components have been reliably fulfilling their function in the railway environment for more than seven years. The decentralized network components deployed in the networked DSTW architecture enable numerous new diagnostic applications, including preventive maintenance. It’s now up to railway network operators to advance this ongoing process of digitalizing their networks and integrate it in the technical and operational goals for their network infrastructure.
Digital interlocking technology
The DSTW is the technological successor to the electronic interlocking (ESTW). Both interlockings use redundant computer systems to check and process the dispatcher’s switching commands. They differ in the way that data is transmitted between the interlocking and the points, signals, axle counters, and level crossings.
The ESTW uses conventional electrical switching technology, often with the aid of extremely long cable bundles. Digital interlockings transmit switching commands using modern Ethernet technology. In addition to a significantly longer control distance, they have the advantage of requiring much less cable. Individual connections to each interlocking element via cable are no longer necessary.
Signaling Technology 4.0
The new DSTW technology is based on standardized interfaces and a new platform architecture. The heart of the project is Trackguard Sinet. This new technology separates the processes of information transmission and power supply. The interlocking system and the field elements exchange data via Ethernet.
The major challenge is to meet DB’s safety requirements for infrastructure technology. Among other things, the control devices from Siemens Mobility are intrinsically safe and are continuously monitored by the interlocking system. Trackguard Sinet offers maximum safety combined with modern mobility technology, including unlimited remote monitoring, outdoor capability, standardized interfaces, and IP-based communication, and it’s also ready for immediate use. Experts at Siemens Mobility are calling it Signaling Technology 4.0.
The company is also using Trackguard Sigrid, a state-of-the-art distributed power supply concept.
An important step toward the future
The next generation of interlocking technology is already in sight: “interlocking in the cloud.”
According to Michael Peter, CEO of Siemens Mobility, “The solutions used in Annaberg-Buchholz and Warnemünde are an important step toward interlockings in the cloud. For the first time ever, an interlocking system is transmitting its IP-based control commands to the system’s field elements, including points and signals. This enables an entirely new level of flexibility in planning, makes it possible to use intelligent field elements, and will generate positive cost effects over the longer term. And of course, all this is achieved while meeting the strictest safety standards for operations.”
Siemens Mobility is already testing cloud-based interlocking technology in individual pilot projects.