# Possibility of High-Speed Ultrasonic Detection of the Internal Material Defects in Rails

## TL;DR

This paper shows that high-speed ultrasonic testing can detect rail defects reliably at 120 km/h using a patented measuring head.

## Contribution

The study demonstrates the feasibility of high-speed ultrasonic rail defect detection using a novel measuring head design.

## Key findings

- Acoustic coupling quality is strongly influenced by fluid flow rate at high speeds.
- Ultrasonic signals remained reliable at 120 km/h, three times the usual speed.
- Proper control of pressing force and fluid flow enables short-time flaw detection between fast trains.

## Abstract

What are the main findings?

At higher speeds, the quality of acoustic coupling in ultrasonic railway inspection systems is highly dependent on the applied fluid flow;

The pressing force exhibited a less significant impact on the acoustic coupling at high speeds.

What are the implications of the main findings?

Proper control of the liquid flow rate and the pressing force makes it possible to keep reliable ultrasonic measurements at high speeds;

The experimental results indicated that it was possible to keep the high quality of the ultrasonic signal at speeds of 120 km/h, which is three times higher than usual;

Flaw detection of working rails is possible in short time spans between fast passenger trains.

Quick and reliable in situ non-destructive assessment of the material structure is especially critical in the case of measurement of rail defects concerning the demands of quick, uninterrupted transportation and safety. This paper presents the test results of a patented measuring head that is able to perform ultrasonic rail defect detection at speeds of up to 120 km/h. The experimental data was collected and discussed. Statistical analysis was performed in terms of bottom echo drop as a function of velocity, pressing force, and film thickness between the sensor and the rail material surface, as well as the coupling fluid stream intensity. The results proved the feasibility of the device for usage at high speeds for the state monitoring of rails in service.