HIMA PLCs help historic Mariazellerbahn railway achieve modern safety standards

© NÖVOG / weinfranz.at

© NÖVOG / Heussler  

© NÖVOG / Heussler

People around the world who love narrow-gauge railways know the Mariazellerbahn (Mariazell Railway) rail line in Austria.

With operations dating back to 1898, this 84-km line reaching from the Lower Austrian capital of Sankt Pölten to historic Mariazell provides daily passenger service for commuters and a scenic adventure for tourists.

As with every railway, the long-term success of the Mariazellerbahn depends on safe and efficient operations. In 2015, HIMA became part of the legendary railway’s success story by providing SIL 4-certified programmable logic controllers (PLCs) that are the modular and scalable core of the railway’s new interlocking system.

Developed by the Austrian company RDCS Informationstechnologie GmbH, the RTMS/ILOCK-RC interlocking system is the newest component of its Rail Traffic Management System (RTMS). The RTMS/ILOCK-RC module can be seamlessly integrated into the overall RTMS, but the autonomy of RTMS/ILOCK-RC as a full-fledged interlocking system guarantees its practical use as a stand-alone product for regional passenger traffic, marshalling yards, engine sheds, and factory and industrial railway systems.

Selected in an EU-wide tender, the RTMS/ILOCK-RC solution is helping Mariazellerbahn railway operator Niederösterreichische Verkehrsorganisationsgesellschaft (NÖVOG) achieve safe operations and lower life-cycle costs.

CENELEC-certified HIMax, HIMatrix PLCs meet need for COTS solutions

The selection of HIMA PLCs for the RTMS/ILOCK-RC solution is part of a growing preference among rail integrators for modular and scalable PLC technology that delivers the cost efficiencies that rail operators want. But commercial off-the-shelf (COTS) hardware such as HIMax® and HIMatrix® PLCs from HIMA isn’t just the basis for economical alternatives to traditional, proprietary systems; it also reflects the latest, state-of-the-art technology in the railway industry.

Interlockings on the Mariazellerbahn rely on both HIMax and HIMatrix PLCs. Both PLCs were used during the RTMS/ILOCK-RC system certification process, and ILOCK-RC certification according to SIL 4 CENELEC EN 5012x standards was achieved in 2015.

HIMax PLCs were designed for safety-critical applications that need to run continuously. They’re also suitable for applications that require extremely fast responses and a large number of inputs and outputs. A plug-and-play system with hot-swap functionality, HIMax allows for fast, cost-efficient and interruption-free replacement of components, ensuring high system availability. Modifications, extensions and maintenance can be carried out during system operation. With physically separated redundant components, HIMax protects against common-cause mistakes.

HIMatrix PLCs were developed especially for applications requiring not more than a few hundred I/O; they’re ideal for implementing cost-effective and efficient solutions. Their high performance, compactness and simple assembly of control modules and remote I/O modules are particularly beneficial in interconnected and time-sensitive applications. HIMatrix components also reduce wiring complexity as they can be used in centralized and decentralized applications.

The following table represents a typical RTMS/ILOCK-RC deployment using HIMA PLCs:

Outdoor installationsPLC familyInstallation location
Small interlocking system
Up to 8 switches
Up to 8 light signals
Up to 8 clear track sections
HIMatrix with extensions at I/O analog and count valuesExternal cabinets as well as interlocking system rooms
ILOCK-RC interlocking systemUp to 32 switches
Up to 32 light signals
Up to 32 clear track sections
HIMatrix / HIMax Interlocking system rooms
Large interlocking system
32 to 512 (theoretically unlimited) switches
32 to 512 (theoretically unlimited) light signals
32 to 384 (theoretically unlimited) clear track sections
HIMax (with several racks)Interlocking system rooms

On the Mariazellerbahn, three train stations (St. Pölten main station, St. Pölten Alpenbahnhof and Laubenbachmühle) are equipped with independent interlocking systems and a common operations control center. These independent RTMS/ILOCK-RC systems and the overall RTMS train safety system, which features driver-cab-signalled train control operations, ensure safe and flawless processes along the Mariazellerbahn rail line and comply with service regulations.

Communication between the logical interlocking system head (ILOCK-HEAD-PLC) and the RTMS/ILOCK-RC PLCs is accomplished via redundant network connections and the HIMA safeethernet protocol (SIL 4 certified, as required by CENELEC EN 50128). HIMA’s SILworX® development interface, also CENELEC-compliant, is used for the interlocking system’s configuration.

As with the overall RTMS, the RTMS/ILOCK-RC system featuring HIMA PLCs is designed to enable railway support staff to significantly increase the protection level of regional routes, industrial and factory railways. HIMA is dedicated to helping railway integrators such as RDCS and rail operators such as NÖVOG develop and operate solutions to make rail travel safer, more efficient and punctual.


Mr. Sedat Sezgün, Head of Rail

Tel.: +49 (6202) 709 - 549
Email: rail@hima.com


To improve safety protection and lower life-cycle costs, the operator of the historic Austrian Mariazellerbahn (Mariazell Railway) rail line selected the ILOCK-RC interlocking system from Austrian company RDCS Informationstechnologie GmbH. Based on CENELEC-certified HIMax and HIMatrix PLCs from HIMA, the ILOCK-RC system provides operators with a modular, flexible and scalable alternative to expensive, proprietary interlocking technology.