Although the use of precast concrete in Australia has been common for many years, it was not widely used in the underground structures. This paper presents the advantages in the application of precast concrete in the new Epping to Chatswood Rail Line (ECRL), the largest publicly-funded infrastructure project underway in NSW, Australia. Its 12.5km of underground passenger rail line will link the Main North Line at Epping to the North Shore Line at Chatswood. The works involve twin underground rail tunnels with one track in each tunnel, three new underground stations at Macquarie University, Macquarie Park and North Ryde, one upgrade of Epping station and nine underground service buildings. Precast concrete has been extensively used at many locations throughout the project. Innovative use of precast concrete construction played a significant role in the success of the project. The ECRL project served as excellent examples to demonstrate that the use of precast concrete in underground structure can be technically feasible and cost effective.