Hoo boy, is this ever a doozy of a project. The Metro Tunnel is the biggest rail project in Melbourne since the City Loop was built in the 1970s and 1980s. Five new train stations will be built as part of the project, and 9 kilometres of twin tunnels will be built. You can have a look at artists' impressions of the five new stations – they look pretty schmick. The new stations will be called North Melbourne (the current North Melbourne will be renamed West Melbourne), Parkville, State Library, Town Hall and Anzac.
The idea is to untangle the City Loop by joining the Sunbury, Cranbourne and Pakenham lines so trains on those lines can travel under the CBD using a new dedicated tunnel. Trains on other lines will continue to use the City Loop. What's the advantage of that? It means there will be extra room in the City Loop for heaps more frequent services.
What if you want to transfer between a City Loop and Metro Tunnel train? No problem; new underground walkways will connect Town Hall Station through to Flinders Street Station and State Library Station to Melbourne Central Station, so you'll be able to get from one service to the other without any hassle.
There will be a bit of hassle during the construction phase, though. By 2025 the Metro Tunnel will be open for business, but until then there will be some necessary disruptions to your travel. And for you to get where you need to go, you need a plan B. See the Victorian Big Build disruptions map for up-to-the-minute updates as to what your plan B should be.