Cracks in railway prestressed concrete sleepers are often caused by the infrequent but high magnitude impact forces. These impact forces are attributed to the wheel or rail abnormalities, e.g. wheel flat, corrugation, dipped joint, etc. The emphasis of this paper is placed on the corresponding fractures of railway prestressed concrete sleepers in track systems under the probabilistic impact loadings. The statistical data of impact loadings in Central Queensland have been obtained through the collaborative project under the research framework of the Australian Cooperative Research Centre for Railway Engineering and Technologies. It is found that for the heavy haul railway network, the track structures, especially the concrete sleepers, may experience the impact loading from 400kN up to 800kN. The corresponding probabilities of such load occurrences are ranging from one in twenty years to one in thousands of years. It is very important for the design and maintenance perspectives to investigate the impact behaviour of concrete sleepers under the impact loadings. This paper presents the impact fractures of railway prestressed concrete sleepers under the single impact loading associated with the probability of occurrence in the soft track environment. Visual interfacial cracks have been evaluated for the crack length and width along the sleepers in relation to the probability of load occurrence.