Which is interesting, given that BITRE tells me NSW doesn’t have a track class standard similar to Victoria. That leads me to two questions that watchers of this thread might be able to answer: is this true? If so, how does NSW categorise tracks instead? And second, how old is the Victorian system and how did it originate?BITRE hasn't been looking hard enough (or aren't willing to do your homework for you). John Holland Country Rail Network has a track class standard - currently defined in CRN Civil Engineering Standard CRN CS 200 - Track System. They have Classes 1/2/3G/3/5.
ARTC has a differently enumerated classification system that is based on traffic - Heavy Haul (i.e Hunter Valley), Interstate (i.e North East Line), Intrastate (e.g Gap-Dubbo line) and Light Duty (branch lines). Speeds and axle loadings are defined in Code of Practice Section 0: Track & Civil Management System and the track construction standards are defined in later sections of the Code of Practice.