Loose bolts pose a severe hazard in rail transport. When high-speed rail train running, high-speed trains and rails continue to contact, the formation of the vibration is very large, the general bolts in this vibration will be loose or even shock. The status inspection and maintenance actions on the mechanical components of trains and tracks are significant determinants of railway safety. Failures due to material fatigue or loose connections can be disastrous.


Our bolt monitoring solutions provides information on the condition of the bolted joints. Users can remotely monitor the tightness of bolted connections, receive early warnings and alarms of bolt failures, and track progressive bolt loosening over time.


Based on non-intrusive sensors, extremely low-power technology, long-life and replaceable internal batteries, and reliable wireless data transmission, our solutions are designed for easy installation and continuous operation without maintenance for years in harsh environment.


We offer two different sensing technologies for monitoring bolt connections:

Bolt Preload Sensing

The function of a bolt is to apply a clamp force, known as preload and measured in Newtons, in a bolted connection. The correct preload ensures the connection’s safety and durability.

A wireless bolt preload sensor is mounted on the bolt head and periodically measures the bolt preload. Each sensor has a built-in ultrasonic transducer. At the time of measurement, an ultrasonic signal is passed through the fastener and reflected at the end. The sensor uses the time-of-flight of the ultrasonic signal and the temperature to calculate the preload, with an accuracy within 2% of the actual preload.

                    Wind Turbine Bolt Monitoring(图1)                           


Bolt Loosening Sensing

While bolt preload sensing technology provides direct and the most accurate measurement, bolt loosening technology offers a cost-effective alternative by measuring the rotation angle of a bolt or nut.


A wireless bolt loosening sensor is permanently clamped on the nut and periodically measures the rotation angle of the nut relative to the bolt, with an accuracy within ±0.5°.

Wind Turbine Bolt Monitoring(图2)

Data collected from sensors are transmitted to a remote monitoring system via a single wireless gateway.


Key Advantages

·         Non-intrusive: No impact on the structure or strength of the bolt.

·         Accurate: High accuracy of less than ±2% of the preload or ±0.5°.

·         Easy-to-install: Compact, lightweight, and mounted with epoxy or clamp.

·         Low-powered: Built-in battery with 10 years of life for normal usage.

·         Ruggedized: Waterproof, dustproof, shockproof, and corrosion-resistant.

·         Accessible: Remotely accessible anytime, anywhere.

·         Intelligent: Early detection of critical bolt damages; continuous monitoring 24/7.


Our solutions increase the safety and longevity of critical assets, reduce downtime by optimizing operation and maintenance activities, and help drive smarter, faster business decisions for rail operators.

Application Cases:

·         Bolt Monitoring System Deployed in Major Subway