The Train Management and Control System (TMACS) is a Communications-based train control system used on over of track in Australia.
Unlike most train protection systems, TMACS does not use balises or any other trackside equipment. Instead, it uses GPS to identify the locomotive's position. TMACS is only used in Train Order territory, where there are no trackside signals, only points indicators and main line indicators.
The CBTC-based system using virtual-block movement authority limits, which are called electronic authorities. The electronic authority replaces a paper-based system of train orders, which operated similarly to Track Warrant Control, and continues to be used on some branch lines in Australia.
TMACS-equipped locomotives must have an In-Cabin Equipment (ICE) unit installed, developed by Base<sub>2</sub>. The ICE unit uses the National Train Communications System (NTCS) to communicate with network control. Data is transmitted using Telstra's 4G network, and Iridium's satellite phone network when 4G is unavailable. For voice comms, UHF radio frequencies are also used to communicate with local train crew.
If the train exceeds the limit of the electronic authority, the ICE unit raises an in-cab alarm. It can also activate the train's emergency brake, but this feature is not yet certificated for use, as of 2025.
TMACS has three levels of safety. Level 3 is not used yet.
TMACS is used on lines operated by the Australian Rail Track Corporation (ARTC), and on the Country Regional Network in New South Wales.