Rail maintenance for long-term operation  

Victoria is the most advanced state in Australia in terms of implementing high-speed rail.  

The approach taken is by building isolated new sections of tracks, one at a time, which can be linked into the existing main tracks.  

Currently, some tracks can already run trains at 160km/hr and more sections are planned.  

Running the train at high speed puts significantly more stress on the tracks. Therefore,  it is crucial to ensure that the health of the tracks is regularly monitored as the train can derail if it runs on the damaged rail.  

Laser profile scanners are ideal for scanning the wear and tear on the rail tracks and have been previously used for this type of measurement application.  

However, as the length of the tracks can span several hundreds of kilometres, it is not desirable to close down the track and scan the whole length of the tracks to identify the area with wear and tear. It is more feasible to develop a mitigating technology that can be integrated in the train itself to minimise the wear on the tracks.  

One of the examples of such technology is the innovative traction system from Actiwheel. It uses artificial intelligence to guide trains along the tracks, which enables quicker, smoother and more economical rail travel. 

Actiwheel – automated rail guiding system 

One of the biggest issues facing the rail infrastructure is Rolling Contact Fatigue (RCF), which occurs due to the energy in the contact between the wheel and the rail.  

Conditions under the contact patch are always severe and the yield stress of the rail wheel is always exceeded, on at least a microscale.  

The system actively yaws the wheels, along with active torque control to manages the contact patch at the optimum point of the rail, which practically eliminates RCF. This is because ideal [close to radial] steering reduces the energy in the contact patch to a point where RCF does not occur and the wear is minimal 

The revolutionary Actiwheel motor can be controlled to produce more driving force on one side or the other in order to steer the wheelset down the centreline of the track.  

For the last 200 years, conventional rail vehicles have only had a solid axle and wheel coning providing this capability which drives some significant compromises and issues. This technology is expected to be implemented for future rail vehicles.  

In the ActiWheel solution, the motor is integrated in the wheel, which means there is no transmission between the two and no moving parts beyond a bearing which every wheel and axle has. In addition, there is no friction braking systems, so there would be a significant reduction in the amount of maintenance required. 

This new Actiwheel solution was developed by UK-based company, SET Ltd. It has proved that it can dramatically change the way rail vehicles run on the railway. It used the optoNCDT 1420 laser triangulation sensors from Micro-Epsilon for this groundbreaking rail-traction technology project. 

Highly precise laser triangulation sensors in Actiwheel system development 

The ActiWheel offers a reliable and highly durable system, to allow wheels to last somewhere between four to 10 times longer .  

There is virtually no wear, which means the rail isn’t being damaged and the wheels don’t deteriorate. This lightweight system also allows additional carrying capacity for passengers without putting much strain when accelerating or decelerating the train.  

SET Ltd is engaged in developing a system for network rail, using the optoNCDT 1420 laser triangulation sensor with an integral controller. The optoNCDT 1420 laser sensor is designed for high precision, high speed, dynamic displacement, distance and position measurement applications.  

The measuring rate is adjustable up to 4kHz. A range of different output signals enables easy integration of the sensor into plant or machine control systems. The data is communicated as analogue voltage and current outputs as well as a digital RS422 interface to provide distance information from the sensor.  

All optoNCDT 1420 sensors operate using a web interface for fast sensor set up and configuration. Additional features of the optoNCDT 1420 include video signal display, signal peak selection and freely adjustable signal averaging, which enables optimisation of the measurement task.  

A region of interest (ROI) function allows background signal noise to be filtered out. SET engineers built a special frame that lies beneath the wheel axle on the train. The optoNCDT 1420 sensors are mounted at a distance of 400mm from the rail head, just in front of the flange radius, pointing directly at the rail head. Measurement data from the sensors is outputted to the ActiWheel control system via 4-20mA. 

The sensors have performed very well in the demonstrator project and on other projects where the ActiWheel system has been tested.  

They are reliable even when used in the harsh operating environment such as underneath a train, where dust, dirt and moisture are present. They also offer reliable operations regardless of the weather, whether it’s a cold, wet, rainy day or a bright sunny day.  

The sensors also do not require cleaning after a couple of thousand miles of testing during the demonstration project. The ILD1420 sensors can also be recalibrated for use in other types of applications which showcase its versatility for any measurement applications in the industry.  

Bestech practice 

Bestech Australia specialises in supplying, designing and manufacturing sensors and instrumentation for measurement of physical parameters, data acquisition systems and technical teaching equipment for teaching and training of vocational and engineering education.  

It also offers a wide range of data acquisition system that can be used with the sensors for mobile acquisition and monitoring.  

Bestech Australia supplies sensors from MicroEpsilon for test and measurement applications in Oceania and complements this with the technical support from its application engineers and product specialists. It assists the clients throughout entire project from design, delivery, commissioning to after sales support. 

 

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