The city loop, or 'the loop' refers to the train stations Flinders Street
, Melbourne Central
(formally known as Museum), Parliament
, Spencer Street
's railway system. Coupled with the tram system we have here in Melbourne, travelling around the city is fairly easy. Melbourne Central
stations are all underground, but look imho
I'm also pleased to note that it's fun watching people's mobile phone conversations cutting out while going on the underground segment of the loop.
Disclaimer: I have not travelled on other railway systems so I am not really able to objectively compare the efficacy of Melbourne's train system.