First to the NSW EPA - always the toughest Australian administation for rail operators, it has new tougher noise and exhaust emission standards on the way that will see any locomotive unable to obtain accreditation banned from operating in New South Wales. How onerous the accreditation process will be is still not public, but it would appear likely any Alco, older GE FDL or EMD 645 will struggle - meaning almost any locomotive built before the early 1990s will no longer be able to enter or operate in NSW. The standards could well impact on even more recently built locomotive types if something like the American Tier-4 standard is adopted.
Since no one, other than the EPA, knows what these new standards will be, it's hard to quantify the outcome, but it's likely any rail operator operating in NSW will have some locomotives that will be need to be replaced or remanufactured in the ten years after the clock starts ticking.
And now, to the rest of the world - with most of Europe banning the sale of conventionally powered vehicles by 2035, and India - plus possibly China - by 2030, it's likely demand for and the production of refined fossil fuels will fall dramatically during the 2030s. With almost all of Australia's refined fuels currently imported, availability of diesel - regardless of Australian energy policies - will be a significant issue for any local industry, including rail. It's almost a certainty that by the 2030s, Australian rail operators will have to begin finding alternative fuel sources in response to diesel supplies - be it bio-fuels, hydrogen, batteries or electrification - which, is likely to have a very significant impact on what locomotives we see around us today surviving into the 2040s.
So get ready - like the end of the steam, there's very likely an end of diesel on the way.