Greetings from the overnight train from Melbourne to Sydney. This is a NSW CountryLink XPT , which left Melbourne's Southern Cross Railway Station on time at 7:55pm and is due at Sydney Central Station at 8:20pm. We are one hour late due to track-works, but that is hardly noticeable in the first class sleeper compartment, with breakfast served on time.
The compartment has three seats during the day and converts to two single bunk beds. There is a shower/toilet shared by each two compartments. Showering on a moving train is a challenging experience, but it is refreshing.
The compartment has a power-point, handy for laptops and mobile charging (although mobile data and cell coverage becomes intermittent outside the city, due in part to the metallic anti-reflective coting on the windows blocking radio signals).
Outside the city there is not much variation in the countryside: trees, fields and the odd cow and horse. This does not quite compare with the Rock Mountains, the Swiss Alps, or Thessaloniki to Istanbul. But particularly for rail enthusiasts, this is one to tick off on the list. You should book soon, as the NSW Government has announced a restructure of railways and the service is likely to be canceled (see: "RailCorp split divides opinion", Ben Neutze, The Current, 16 May 2012).
ps:Warm Nights on a Slow Moving Train was a 1988 film by Bob Ellis with Wendy Hughes and Colin Friels, set on a NSW overnight train. This trip did not have quite that excitement.