Sydney Metro City & Southwest is a 30 km (19 mi) rapid transit project currently under-construction in Sydney, New South Wales, Australia. The project will extend the Metro North West Line from Chatswood on the North Shore, to Bankstown in the city's south-west via the Sydney central business district. The centrepiece of the project is a new 15.5 km (9.6 mi) twin-tunnel rail crossing under Sydney Harbour and through the city to Sydenham. Together with planned improvements to the Main Western line, the project is expected to increase capacity on the Sydney rail network by up to 60%, and allow for the movement of over 100,000 extra commuters across the network every hour.