Given it has a safety component wouldnt there be scope for some sort of mandatory requirement on the part of operators?
In aviation there are airworthiness directives, including those that specify that you need to have xx equipment for xx safety reason. Are there the equivalents in rail and if so, who is the regulator? ATSB?
ATSB are investigators, the regulators are the Office of the National Rail Safety Regulator (http://www.onrsr.com.au/
I would hazard a guess, that ARTC would be responsible for the installation of the equipment, as they are changing the rules such as they did with the requirement that ICE be the new radio standard equipment to access the network.
In terms of the rail industry, the basic framework work around something like this:
Regulator sets the standards for accreditation.
Transport investigator provides recommendations where standards have not been followed, were insufficient or lacking to prevent an incident
Network manager implements recommendations, sets operating requirements and forms interface agreements with operators based on the accreditation requirements set by ONRSR
Operator follows directives of network manager to ensure compliance with standards and accreditation requirements. Additionally, they also must implement risk based control measures to ensure ongoing improvement and monitoring of rail operations from their side that complement the standards outlined within the accreditation license that has been issued to them. For a specific example in regards to that point, PN are accredited to run driver only from Adelaide to Port Augusta. SCT are not, because they do not have the license nor operating accreditation and supporting systems to do so.
The duties of the National Regulator may be carried out by state based regulators, such as in the case of the NSW but under national rail safety legislation, still answerable to the head office of the national regulator.