Network Rail has awarded full product acceptance (PA05/07464) of Bender UK’s RS4 Tier 2 Intelligent Insulation Monitoring System after numerous live trials of the equipment. Bender’s rail signal power monitoring technology is designed to pinpoint and locate earth faults on the UK’s rail infrastructure.

RS4 Tier 2 system measures insulation resistance and leakage capacitances to individual feeder levels on rail IT electrical systems up to 690V, in addition to delivering the overall system resistance and capacitance provided by the RS4 Tier 3 system.

Comprehensive data readings and information on the status of miles of networked cables enable operators to make a clearer overall assessment of the system condition and plan predictive and preventive maintenance to prevent downtime.

RS4 Tier 2 is the most cost-effective solution for upgrading previous generation Bender rail technology and can be installed with simple mechanical and wiring modifications onsite.

Tier 2 compliance is achieved through the incorporation of Bender Type B current transformers (CT) and Bender COM465IP condition monitor to enable complex individual feeder measurements.  It is also fully upgradeable to deliver a Tier 1 solution.

RS4 was developed collaboratively with Network Rail in response to standard NR/L2/SIGELP/27725 Tier 1, 2, and 3 designed to reduce maintenance, service failures and improve staff safety by minimising trackside intervention, termed ‘boots on ballast’.

In addition, Bender is conducting live trials of RS4 Tier 1 equipment at multiple locations with approval expected in early in 2022. The RS4 Tier 1 will increase the functionality level to provide accurate individual cable section and FSP switchgear level insulation resistances.

For over two decades Bender has pioneered the development of rail signal power monitoring in the UK, with thousands of Bender systems already installed and proven in use on the UK’s rail network. The roll out of RS4 Tier 3 began in early 2020, following full Network Rail product approval.

Bender UK offers a full range of managed support services designed to offer the best strategic fit and greatest value for money for the rail industry, balancing benefits with affordability to improve the efficiency of rail network maintenance, enhance safety and reduce operating costs for the network.  These include remote condition monitoring technologies designed to integrate seamlessly with future smart infrastructure, and advanced analysis of the data collected by monitoring Bender and third-party devices to identify trends and minimise the risk of failure, power loss and shutdown.

For more information visit contact