Wheel Impact Monitoring and Weigh in Motion (WIM-WIM) System used in Monitoring Critical Infrastructure, Research & Developments Launches in Australia

OVERVIEW OF THE WIM-WIM SYSTEM

The WIM-WIM system is designed to accurately measure the forces exerted on the rail infrastructure across a broad spectrum of operational velocities. This enables the capture of real-life force data ranging from high-speed rail operating conditions down to low speed. The data is of crucial importance as it represents a direct consequence of the dynamic interaction between the rolling stock and the track, providing invaluable insights into the mechanical stresses experienced by the railway system.

The WIM-WIM system includes a powerful high speed data acquisition & analysis system which amplifies, and analyses strain gauges directly applied to the railway line, across 12-16 sleepers’ length on both rails, providing highly accurate measurements.

These measurements are calibrated precisely to the vertical and lateral forces (or tons) inferred in the railway line caused by the train, locomotive, wagon, or rail vehicle being measured. The vertical forces can be attributed to weight and impacts on the rail due to defects in the wheel/suspension. The lateral forces can be attributed to the forces pushing the rail inwards or outwards parallel to the ground such as skew or flanging bogies.

The length of the system is such that the circumference of each train vehicle wheel is measured at every point on the wheel approximately 2.5 times. The weight of each wheel is measured and analysed individually. This data is then used to calculate the axle weight, bogie weight, overloading, unbalanced loading, and impacts caused by any faults that the vehicle may have.

The information that is generated is comprehensive and the reports are sent to the rail operators back-office system for proactive action. Gamma Engineering can further integrate with other systems and develop bolt on analysis systems.

The information of the vehicles is paired with a RFID tag reader or a vehicle database which can accurately detect the type of locomotive from the vehicles unique geometry signature.

CRITICAL INFRASTRUCTURE BEING PROACTIVELY MONITORED BY THE WIM-WIM SYSTEM

The system is used widely in South Africa on the heavy haul coal (26t/axle) and iron ore (30t/axle) lines, as well as general freight lines.

The Olifants River Bridge in South Africa is one of the most critical pieces of infrastructure to South Africa’s heavy haul iron ore export operations. The bridge is 1km in length and crossed by the longest heavy haul train in the world ( as of 2017) at 4.1 km in length.

The WIM-WIM system has been used in numerous University, independent and Transnet studies to analyse the data and the effect of increasing capacity of the heavy haul line on the bridge.

Proceedings of the 11th International Heavy Haul Association Conference (IHHA 2017), Cape Town, South Africa; How testing and monitoring can support heavy haul railway bridge management: the experience gained in South Africa; F. Busatta & P. Moyo; Concrete Materials and Structural Integrity Research Unit, University of Cape Town, Cape Town, South Africa

Proceedings of the 11th International Heavy Haul Association Conference (IHHA 2017), Cape Town, South Africa; Increasing capacity on Transnet’s general freight operations through running longer trains - a case study of the chrome railway system; L. Ratshilingano & B. Monakali; Transnet Freight Rail, Johannesburg, South Africa

ADVANTAGES OF WIM-WIM DIRECT STRAIN GAUGE BASED METHOD

Accuracy and Sensitivity: Direct strain gauges provide highly accurate measurements of strain because they are attached directly to the surface where deformation occurs. This direct contact allows for the detection of minute changes in the material, whereas bolted-on systems may introduce their own strains and residual stresses, potentially affecting the accuracy of the measurements.

Data Acquisition Frequency: Strain gauges are analogue and can be digitized at extremely high frequencies. The dynamic interaction between the rolling stock and the track can be measured and classified as soon as it happens, resulting in maintenance being done on vehicles. This includes operating speeds and vertical force impacts up to 70 tons.

Resolution: Strain gauges can detect very small strain levels, which is beneficial when precise measurements are critical. Bolted-on systems may not be as sensitive to small deformations due to their bulkier and more rigid nature.

Frequency Response: Direct strain gauges can measure rapidly changing strains, offering excellent dynamic response characteristics. Indirect methods may not be able to accurately capture high-frequency data due to the inertia of additional components.

Size and Weight: Strain gauges are small, lightweight, and can be easily applied to a variety of surfaces without significantly altering the structure’s mass or dynamics. In contrast, bolted-on systems add weight and may alter the structural dynamics or introduce additional stress concentrations.

Versatility: Direct strain gauges can be used on a wide range of materials and shapes, including complex geometries where bolted-on systems might not be feasible. They can also be arranged in various configurations to measure different types of strain, such as tensile, compressive, or shear strains.

Ease of Installation: Strain gauges can be bonded to a surface with relative ease compared to the installation of bolted-on systems, which may require drilling and other modifications that could weaken the structure.

Cost-effectiveness: The initial cost of strain gauges is generally lower than that of bolted-on systems. They also tend to have lower maintenance costs since there are fewer mechanical parts that can wear out or require calibration.

Minimal Structural Impact: Direct strain gauges do not compromise the integrity of the structure as they do not require any drilling or significant alteration to the surface. Bolted-on systems may necessitate permanent modifications that could affect the performance or integrity of the structure.

Temperature Compensation: Strain gauges used in WIM-WIM have built-in temperature compensation, which is crucial for accurate measurements in environments with fluctuating temperatures.

Data Collection Efficiency: Data from strain gauges is collected and analysed quickly, and reports of full vehicles data generated in seconds.

Minimal maintenance as the strain gauges are protected with steel cover plates, weatherproofed and heat shielded.

These advantages make direct strain gauges a preferred choice in many engineering applications, especially when high fidelity and accuracy are required.

WIM-WIM AS A RESEARCH TOOL AND DEVELOPMENTS

Additional research and improvements are currently being developed by Gamma Engineering.

The effect of the longitudinal forces in the rail (temperature fluctuations in the rail, causing the rail to extend or contract leads to tension or compression in the rail due) on the vertical and lateral force measurements.

Steel, like most materials, expands when heated and contracts when cooled. This is described by the coefficient of thermal expansion, a material-specific constant that quantifies the change in dimension per degree of temperature change. For steel rails, the expansion and contraction due to diurnal and seasonal temperature variations can be considerable due to the length of the rails.

Gamma Engineering has developed a IIOT device for measuring longitudinal stress in the rail. This sensor will be used to determine these effects with the objective to further increase the accuracy of the WIM-WIM system.

Another development to be tested is the angle of attack of the bogie axles using the data obtained by the WIM-WIM system. Algorithms have been developed and calculated based on individual axles using a simulated version of the WIM-WIM system.

WIM-WIM AS A SOURCE OF BIG DATA FOR ADDITIONAL ANALYTICS & ANALYSIS

As the data is being consumed and stored primarily on a rail operators’ infrastructure, routines have been developed to use the data as a tool for Early detection and monitoring of polygonised wheels to reduce the maintenance cost and increase the operational availability of affected rolling stock.

“…an alternative processing technique, able to extract the amplitude and order of wheel tread polygonisation, was developed. By using data from an existing measurement system, a low-cost solution that allows for specialised analysis of out-of-round wheels was obtained. A sensitivity analysis revealed that the technique had very good reliability across all realistic speed, dynamic loading, and order scenarios”.

Proceedings of the 11th International Heavy Haul Association Conference (IHHA 2017), Cape Town, South Africa; Identification and monitoring of polygonised railway wheels using existing wheel impact monitoring measurement data; E. Reitmann, R.D. Fr?hling & G. Hettasch; Transnet Freight Rail, Pretoria, South Africa

SUPPORT / INSTALLATION / CALIBRATION & MAINTENANCE ARE AVAILABLE ?IN THE FOLLOWING COUNTRIES:

WIM-WIM SYSTEMS AUSTRALIA CONTACT GAMMA ENGINEERING PTY LTD [email protected]

OR MGC SOLUTIONS

[email protected]

WIM-WIM SYSTEMS SOUTH AFRICA CONTACT TLC ENGINEERING SOLUTIONS PTY LTD

[email protected]