Transfield Services has been awarded contracts worth A$200m ($179m) to upgrade rail networks by the Australian Rail Track Corporation (ARTC).
The company said it has been awarded A$160m ($143m) in rail upgrade work for the next two years.
Transfield also secured an 18-month extension of its existing maintenance alliance contract worth A$40m ($35m), bringing the total value of the project to A$200m.
The upgrade work will be carried out in South Australia and the eastern rail corridor between Melbourne and Sydney.
The company expects the work to enhance the efficiency of rail infrastructure, allowing increased freight loads.