Evident
Intelligent Railway Wheelset Inspection Using Phased Array Technology
By DTEC GmbH and Olympus IMS
DTEC GmbH is an NDT equipment supplier located in Frankfurt Rhein-Main, Germany. The company specializes in turnkey solutions for flaw detection in railway wheelsets and train condition monitoring.
Using an advanced phased array ultrasonic testing (PAUT) technique and machine
vision, DTEC GmbH has created intelligent automated systems that provide inspection services for railway safety.
DTEC GmbH’s automated inspection system solutions are used to perform:
- Wayside wheel inspection
- In-service wheel and axle inspection when wheelsets are on train
- Routine wheel and axle maintenance phases when wheelsets are dismounted from the train
In railway maintenance depots and workshops, specialized automated wheel inspection systems (WIS) detect manufacturing flaws, defects, and fatigue cracks in high-speed train, locomotive, and rolling stock wheels and axles. These advanced WIS systems use Olympus’ FOCUS PX PAUT instrumentation.
“The Olympus FOCUS PX makes our star product, the Underfloor Wheelset Ultrasonic Testing System (UW-UT, or UFPE in German), an excellent solution for modern railway maintenance depots. It enables them to inspect wheels for fatigue cracks without needing to remove the wheelset from the vehicle,” says Dr. Eric Peng, Chief Engineer at DTEC GmbH.
The Challenge: Inspecting Wheelsets without Dismounting Them
On trains, wheelset components are subjected to the highest loads. Both wheels and rails are susceptible to rolling-contact fatigue (RCF), which is when cracks grow due to the contact stresses between a rolling wheel and the rail. RCF can induce spalling (flaking) and shelling defects in the wheel tread. Some subsurface and inner defects can develop circumferentially and cause the wheel rim to lose chunks of material. Bulk material loss is dangerous and can result in a derailment. Monitoring the rail-wheel contact and the continuous cycling stress of the axles can help avoid component defects before they cause a failure.
Railway operators can use conventional ultrasonic testing (UT) to conduct periodic NDT inspection of train wheels. However, with the manual UT method, inspectors are unable to achieve full 360-degree-circumferential flaw detection of wheels, mainly because of the complicated structure of train cars’ undercarriage.
Compounding the inconvenience of manual UT, this kind of inspection work is normally scheduled during the night shift to limit the impact on the vehicle’s operation time. In some cases, the wheelsets must be removed from the vehicle, which exponentially increases workload time and cost. The challenge DTEC GmbH faced was to implement an efficient, accurate, reliable, and automatic UT system for wheel inspection while keeping the wheels on the vehicle.
