This paper presents lab trials from an ultrasonic technique capable of reliable sub-surface inspection of cast high manganese steel railway crossings. Volumetric inspection of the component is achieved using a combination of low frequency ultrasound and an advanced ultrasonic technique known as Synthetic Aperture Focussing Technique (SAFT) which uses spatial averaging to reduce back-scattered noise from grain boundaries. The application of the ultrasonic SAFT technique is discussed, and results from empirical studies are presented before finally offering concluding remarks on the future of the technology.