Systematic review: Ultrasonic technology for detecting rail defects

Defects in the rails can affect the operational safety of the railway. In order to examine the knowledge structure of the research about the ultrasonic testing of rail defects, a systematic discussion of the research on the detection of rail defects by ultrasonic technology is conducted. Three development stages in the field of ultrasonic detection of rail defects were revealed using main path analysis, and the themes of five current research hotspots in the field were clarified. These analyses were done for the 371 academic publications published between 1992 and 2022 using bibliometric methods. The most influential nations, academic institutions, and academic journals in the field today are introduced using the visualization technique. Previously, no review articles using the bibliometric method in the field of ultrasonic detection of rail defects had been published. The development direction and research suggestions for ultrasonic detection of rail defects are presented based on the study's findings.