What project is a rail infrastructure project that includes a twin rail tunnel and the building of the Arden railway station?  
Arden railway station, Melbourne: Arden railway station is a planned station to be built as part of the Melbourne Metro Rail Project. Melbourne Metro Rail Project: The Melbourne Metro Rail Project (marketed as the Metro Tunnel and formally known as the Metro Rail Capacity Project), is a metropolitan rail infrastructure project currently under construction in Melbourne, Australia. Melbourne Metro Rail Project:  It includes the construction of a twin rail tunnel between South Kensington station (north west of the Melbourne City Centre) and South Yarra (in the south east) with five new underground stations.
Melbourne Metro Rail Project