Development near planned rail corridors may be required to demonstrate that impacts from the development do not compromise corridor requirements or structural integrity of the future rail infrastructure. The converse requirement occurs when the new tunnel/station cavern is constructed in close proximity to existing multi-storey developments and the removal of ground to form the tunnel could cause disturbance to surrounding ground mass hence potentially adversely affect existing buildings. This case study presents an assessment of potential geotechnical and tunnelling interaction associated with construction of the proposed development of a multi-storey commercial building with deep basements in close proximity to a future Sydney CBD Rail Link station through detailed ground investigations and Phase2 numerical modelling. The study demonstrates how appropriate numerical analysis can be a valuable method in assessment of the mutual influence between underground infrastructure and high-rise building foundations/deep basement excavations.