In railway signaling technology, the demands for safety, availability, and high-performance data acquisition are constantly increasing. Train detection systems today must not only operate reliably, but also be flexible, require little maintenance, and be environmentally resistant. One solution that combines these requirements is the axle counter duo consisting of the AXM module and the UniAS wheel sensor. Together, they form the operational core of the UniAC[2] axle counter system from voestalpine Railway Systems.
The UniAS wheel sensor: Precision on the road
The UniAS wheel sensor plays a central role directly on the track: the reliable detection of train wheels. Accuracy and robustness are crucial here. The UniAS sensor is IP68-certified and therefore completely dustproof and waterproof . Furthermore, it operates reliably in a temperature range of -40 °C to +85 °C , thus ensuring dependable wheel detection in snow, heat, or heavy rain.
Another advantage is the sensor’s high immunity to electromagnetic interference . Thanks to intelligent algorithms, it is compatible with a wide range of rail vehicles – from light rail to high-speed trains . UniAS also features a modular mounting clamp that fits most standard rail profiles, enabling easy on-site installation . This eliminates the need for extensive engineering and construction work.
In short: UniAS is not just a sensor – it is a robust, adaptable and safety-certified detection solution designed for high availability.
AXM Module: The Art of Axle Counting
While the UniAS wheel sensor collects the data, the AXM module handles the central processing. It acts as the “brain” in the technical rooms and is responsible for evaluation, counting, communication, and system monitoring. UniAC[2] uses a single multi-purpose module type , the AXM, which can be configured to fulfill all the necessary functions of the axle counting system, depending on the application scenario. This reduces the need for spare parts, simplifies logistics, standardizes training, and lowers life cycle costs.
Each AXM module can manage up to four counting sections and supports both centralized and decentralized layouts. This allows engineers to plan layouts more efficiently, regardless of whether the installation covers a small station or extensive rail networks. Furthermore, AXM supports several secure interface methods – including protocol-based communication, optocouplers, and relays. This, in turn, enables seamless integration with interlocking systems, level crossing systems, and CTC/ETCS components.
Why they are so compelling together: Synergy at the system level
The full potential of the UniAC[2] axle counting system is only realized through the interaction of the two technologies. The AXM module together with the UniAS wheel sensor offers the following advantages:
SIL4-certified train detection
Both AXM and UniAS operate within a system certified to CENELEC SIL4 – the highest safety standard for functional safety in railway signalling technology. This ensures reliable, fault-tolerant operation even under complex network conditions.
Reduced trackside electronics
The system architecture eliminates unnecessary external electronics and moves critical processing operations indoors, thereby reducing failures and improving long-term reliability.
High EMC resistance
The 20 mA current loop interface between the UniAS sensors and the AXM module makes the system extremely resistant to electromagnetic interference. This is a crucial factor – especially in electrical railway and heavy-duty environments.
Plug-and-play installation
The combination supports a plug-and-play configuration, which reduces on-site setup time and enables quick commissioning.
Future-proof digital architecture
Both components are part of a platform designed for future integrations, including the secure communication protocol EULYNX SCI-TDS and the EULYNX interfaces SMI, SDI and SSI for diagnostics, maintenance and secure operation.
From the reliability of the UniAS wheel sensor on the track to the flexible and intelligent design of the AXM module – the interplay of both components sets standards in axle counting and combines key requirements of modern systems. Namely: high availability, low maintenance, cybersecurity through design, operational flexibility, and a modular, scalable architecture
This article was originally published by voestalpine Railway Systems
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