Strukton develops magnetic sensor to further reduce not-in-control errors

23 April 2015

Strukton engineers have developed a magnetic sensor to measure the status of interlocking relays. The sensor is expected to bring a 5 to 10% reduction of not-in-control errors according to experts. The sensor, in addition to the use of current clamps, will substantially improve the performance of points. The main contribution of the Relay State Sensor Strukton (RSSS) is to avoid repeating failures. The sensor is designed to remotely monitor the entire functional model of a point. Maintenance teams will get a total overview of the track circuits to analyse the cause of point errors.


Strukton’s magnetic sensor is a new feature in the POSS® railway condition monitoring concept. The RSSS is featured by the daisy-chain solution to loop to other sensors and eventually decrease the amount of cables and the amount of inputs on the POSS data loggers. The production is fully implemented by Strukton to control the design and quality of the sensor. The RSSS is developed to determine the position of a point relay in terms of the R/N position of the point. It provides information about the status of the interlocking relay, i.e. is the interlocking relay energised or not. The magnetic sensor, not being a qualitative sensor, will not measure the amount of current and is unlikely to detect certain degradation.

Easy installation

Installing the magnetic status sensor is done by simply clipping it underneath the interlocking relay by a hook and loop fastener. This means that there is no need to disconnect the wiring of the interlocking. The LED light is used as a position indicator; green indicates the right position for making measurements. No galvanic connection is needed for the RSSS to monitor critical relay assets, which is naturally important in the field of rail monitoring.

Current clamps

Strukton has also developed a new type of current clamps to be used for measuring the amount of current used by a point mechanism. The new current clamps are cost-effective and smaller than the current clamps that are common in the market.

About POSS

POSS® is the Dutch abbreviation of Strukton’s Preventive Maintenance and Fault Diagnosis System. Strukton has developed the system to optimally perform its maintenance contracts. The aim: contribute to optimally reliable, available, maintainable and safe railways. Strukton combined its international railway maintenance expertise with its technological expertise for the development of POSS®.