Abstract:Under the repeated load of the wheel, the rail tread is prone to fatigue cracks. Rail tread cracks are typical rolling contact fatigue cracks. These cracks can extend from the railhead to its downside, and it may cause the breakdown of the railhead. It brings hidden huge damage to transport safety. Firstly, the finite element method is used to analyze the interaction law between ultrasonic surface waves and the cracks in the rail tread. The scattering features and ultrasonic reflection behaviors of the lowfrequency surface waves are analyzed when inclination angles and depths of the cracks on the tread change. Secondly, a surface wave electromagnetic acoustic transducer (EMAT) with a center frequency of 03 MHz is designed and established. Then, the Bscan imaging inspection is performed on the rail tread with oblique cracks to identify the cracks intuitively. To improve the worse signaltonoise ratio (SNR) of the EMAT with a larger liftoff and conducting highspeed detection, the crackreflected ultrasonic echo is denoised and reconstructed by synchrosqueezed wavelet transform (SWT). The Bscan images can be rapidly constructed by using SWT. Results show that the designed surface wave EMAT can effectively detect multiple cracks in the rail tread. SNR of the ultrasonic echos is improved at least 883 dB by using SWT denoising method. In addition, the clarity of the Bscan image and the detection efficiency are effectively enhanced.