This is exactly what it sounds like, an abandoned railway tunnel in a town called Tunnel.
If you’re in North East Tasmania, this is a great little adventure to embark on. You’re going to find an old abandoned train tunnel, and that’s about it. People have been walking through it for years, but recently there was a news article that advised visitors to refrain from doing so. You can find article here. If you do choose to venture into the tunnel, explore at your own risk.
The tunnel takes a minimum of 15 mins or so to walk through depending on much water has filled the tunnel. Flash lights are optional but quite helpful. Your phone flashlight might be sufficient.