Rail sensor goes ultrasonic to grease the wheels

UK engineers are working on an ultrasonic sensor for the rail industry that can detect sections of track where vital lubrication has been worn away.

rail sensor
(Credit: Huddersfield University)

The project is a collaboration between Network Rail, Sheffield SME Tribosonics and Huddersfield University's Institute of Railway Research (IRR) and is funded via the EU’s Shift2Rail programme. Tribosonics will develop the detection system and hardware, with sensor development and testing carried out at the IRR’s HAROLD full-scale bogie test facility. According to the researchers, the sensors will be embedded in the wheels of trains and will allow track conditions to be almost continuously monitored.

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“It is not commonly known outside railway circles, that in curved track, a special type of grease is applied between the wheel and rail,” said IRR assistant director Professor Paul Allen, who developed the concept for the sensor. “This lubrication is applied to reduce wear but also the risk of derailment, whereby in some circumstances the wheel can climb up and over the railhead.

“This measurement technology will provide an automated vehicle-mounted system that will communicate to Network Rail the presence of lubrication, and critically, locations where it is absent, thereby reducing maintenance costs and improving railway safety.”

Network Rail currently relies on manual inspection to ensure appropriate levels of lubrication are in place across the UK’s rail lines. As well as being time-consuming, this method is sporadic by nature and can only provide periodic updates on the condition of tracks. By automating the process, the operator will have real-time information on the levels of lubrication across the network, allowing better maintenance planning and improving safety.

“Embedding ultrasonic sensors into the wheel provides the opportunity for continuous monitoring of lubrication effectiveness and allows preventative measures to be applied before problems arise,” said Matthew Harmon, engineering manager at Tribosonics.

Experimental trials will be conducted under real-world conditions, with axle loads of up to 25 tons and a goal of operating at speeds up to 200km/h. According to Network Rail project lead James Lineton, the sensor could have applications beyond the UK and has the potential to disrupt how rail infrastructure is managed around the world.

“By reducing downtime for maintenance activities, we can increase capacity, ultimately improving train availability for passengers,” he said.