In Australia, there has been a notable increase in the construction and maintenance of railways, and it is anticipated that these expenditures will continue to be substantial. This can be attributed to the significant expansion of urban and regional populations, the ongoing growth of trade activities, the environmental advantages associated with rail transportation compared to road transport, and an increasing need for maintenance services. Waste rubber derivatives applied in the ballasted railway substructure have shown improved energy-absorbing characteristics while satisfying engineering properties stated in railway specifications. The laboratory outcomes have been further investigated in an instrumented ballasted track stretch constructed near Sydney, Australia, by including innovative rubber derivatives within the track formation. This paper discusses the application of rubber intermixed ballast replacing the conventional ballast layer and assesses the performance of the modified track substructure compared to a conventional track. Onsite instrument data were utilized to analyse stress distribution, and vibrations in order to assess track performance.