The global oil supply/demand situation, on top of likely carbon pricing, would certainly point towards rail becoming far more economic within the next decade, so the question is whether it makes more sense to keep the railways maintained in readiness for a likely rebirth of rail transport, or just let them lie idle and fix them up when they're needed. I would suspect the latter, given that the current lines are probably not really suitable for supporting modern high speed trains that would be the logical replacement for road-based transport (further, ideally they would be electrified).
As long the rails aren't getting actively ripped up, and the land devoted to other purposes, it may not matter too much.

As fuel prices go up rail transport will become a more economical option.

Gibo, I dont know about visions and prophesies - generally wouldnt be mentioning those unles you want to be treated like a raving looney. BUT basic maintainance of a system in the anticipation of future defence requirements is not a bad idea. Dont see much immediate threat, but that said world situations can change fairly rapidly, and it would certainly be a prudent and conservative consideration. And given the money that we spend on new fighter jets, the basic maintenance of existing rail networks wouldnt break the budget. Ideally we would have more than 1 north-south line, otherwise we leave ourselves wide open to easy sabotage in the event of the worst case scenario.

Railways are not very useful from a military perspective. They are too easy to destroy, which is why they are among the first things to go in a war. How many helicopters, trucks and offroad vehicles does the army own? Compare this wtih how many trains they own.

Being labelled a raving looney wouldnt bother me at all Country Gal. Theres a world out there that hardly any of you folk on this forum site have even heard about (no offence of course). Its a world of born again christians who are completely on-fire for Jesus Christ every moment of their waking day. Of born again christians filled with the Holy Spirit and speaking in "other tongues", of born again christians receiving visions and Words of Knowledge from God and prophecies about future global events, of miracles and healings and even the occasional raising of a dead person. Its the world of Gods Holy Spirit and how He Communicates to people. Its more real to born again christians than the (supposedly) real world you folk live in. Its in this world, amongst the committed christian churches, many of them pentecostal, that visions and prophecies of an invader because of the sins of the people have been coming. The first vision I came across was in Pastor Jack Burrells book WHAT WILL BECOME OF AUSTRALIA 1975 which travelling greatly through the Assembly of God churches during the 70's and 80's. Yep, I believe an invasion is likely in the next 10 years or so. And it will happen fast with a sudden drastic change in the worlds military climate. Those railway tracks are vital to those days.

While sitting on a committee concerned with transport for people with disabilities I was told by one state government official that the ultimate aim was to close down the passenger rail service on the Adelaide Hills Line. They cut it back to Belair and then tried to cut it back to Blackwood when there was a fire at the Belair station. The service has to use a single track working because of the difference in gauge and it runs late so frequently we are all used to catching the train before the scheduled one.
They would still like to close it and passenger numbers are dwindling except at peak hours...dwindling because the service is unreliable and too infrequent.
The problem is that for some people, especially people with disabilities it is the only service which can take wheelchairs and gophers - and then the drivers grumble about having to put the ramp down.
The service is not there - delinerately so. But, is the railway line worth keeping? Absolutely! If it once again ran to Bridgewater or, better still, Mt Barker and did so frequently and on time people would use it. This would not suit the government which is propping up the car industry in this state, or the car workers or the oil companies.