Ultrasonic Wheel Rail Flange Thickness Testing

The railway system is a unique combination of geometry, balance, and engineering, where even the slightest discrepancy could be catastrophic. A piece that’s—at most—twenty-two millimeters thick could spell the difference between an on-time train and a derailment. Wheel rail flange thickness is a central safety component in the railway industry, but it’s also an area rife with potential flaws.

Checking the thickness of these flanges is imperative, though it can be a challenge with all the various factors that can impact them. Speed is essential to keep trains on schedule, but a train can have many flanges, making testing a time-consuming task. Ultrasonic wheel rail flange testing is an effective way to keep these inspections on track and trains on time. 

Wheel Rail Flange Thickness Challenges 

Train wheels have a unique geometric shape to move around bends while staying on the track. The flange plays a central role in this. After reaching the limits of geometrical control, they take over and keep the wheel connected to the rail. However, they’re only tiny pieces, usually between fifteen and twenty-two millimeters in thickness. If the flange dips below this, there can be issues. Unfortunately, compromised flanges aren’t uncommon. They are challenging to check and prone to damage. Here are just a few obstacles in wheel rail flange management and testing. 

• Heat: Blocks applied to the wheel surface during breaking that create intense thermal energy. If extreme enough, or under repeated circumstances, the heat can be enough to alter the flange’s dimensions.  
• Friction: Flanges are under near-constant friction, as there are no rail routes that are 100% straight. Wherever they go over a bend, they can rub against the rail, causing wear over time, leading to thinning. 
• Stress: Flanges have to support massive amounts of weight while in motion. The pressure of this is enough to break down the metal properties and cause damage that can compromise the flange’s efficacy. 
• Quantity: Every wheel on the train has a flange, and all must work in unison to ensure safe operation.   
• Speed: Trains operate on extremely tight schedules with rail use mapped carefully. A delay due to testing can have a domino effect that impacts the entire rail system. 
• Position: The flange location isn’t exactly easy to reach—nor is it practical to remove all the wheels for testing. Any testing mechanism will need to be flexible to ensure access and accuracy. 
• Risk: A flange defect can lead to catastrophic results, so it’s imperative that testing be accurate. Even a minor derailment is enough to create massive damage and delays. 

With all these risk factors, it’s essential to create a proactive yet simple means of measuring wheel rail flange thickness to ensure its functionality. For this reason, nondestructive testing in the railway industry is in high demand. 

Using Ultrasonic NDT to Speed Train Inspections 

In-service ultrasonic nondestructive testing (NDT) allows individuals to test their wheel rail flange thickness with minimal downtime. In the traditional method, equipment fires a single ultrasonic beam into the part. The probe receives a return signal, and echoes within that signal can indicate a flaw or thinning material in need of replacement. 

Traditional ultrasonic testing (UT) has some limitations. The accuracy of the test is highly dependent on the angle and focal point of the beam. As flanges are in a spot that’s often challenging to test, this limited array may not be sufficient to ensure the capture of all flaws. 

Phased array ultrasonic testing (PAUT) is a far more suitable solution. It leverages a grid of 16 to 64 elements within a single probe. This arrangement allows for multiple angles and focal points to capture a more significant number of flaws. A PAUT approach is especially advantageous when distortion limits the ability to test specific locations or depths within the material. When seeking out equipment to manage such inspections, it’s wise to look for several key features: 

• Powerful, on-board software: Much of this testing will occur in the field, so it isn’t likely that the inspector will have the time or opportunity to upload the results to a computer. Ultrasonic NDT with highly capable on-board software allows for real-time testing needed in the busy railway industry. 
• Portability with performance: It’s often easier to bring the equipment to the wheel than bring the wheel to the equipment. A portable, high-performance UT unit will ensure rapid testing of multiple components without the need to disassemble axles. 
• Traceability: The railway industry is fraught with regulations, so it should be possible to save and prove tests. The software supporting the ultrasonic equipment is just as essential as the equipment itself. 

Selecting ultrasonic NDT equipment with these features is the best way to manage wheel rail flange thickness testing. A lot can go wrong with these small components, so the ability to test quickly and effectively is critical. The right portable PAUT unit can help manage needed inspections while minimizing downtime. 

Zetec ultrasonic NDT equipment is ideal for wheel rail flange thickness testing as it’s portable and includes on-board software for traceability and real-time testing. Visit our contact page for more information.