trains; local trains operated by MTR Corporation use TBL as of 2012, enhanced with ATP/ATO - due to be upgraded to CBTC by 2021) Queensland, Australia; sometimes enhanced with ATP. At the other extreme Queensland also provides a permanent magnet at the fixed distant signal of unattended crossing loops. This is also sometimes comes with AWS Signs. Adelaide, South Australia Taiwan Railways Administration EMU100, EMU200 series (used alongside ATS-SN/ATS-P, replaced with ATP in 2006) Experimental French system, half mechanical and half electrical (1913) Liberia; One of the mining railways in this country had a more advanced AWS system that employed two or three magnets of either polarity and located near the rails to avoid the suppression problem. The system was therefore able to give more aspects than the BR version. See also Anti Collision Device Automatic Train Protection Continuous Automatic Warning System Crocodile (train protection system) Driver reminder appliance Intermittent Inductive Automatic Train Stop Positive Train Control Train Protection & Warning System Automatic Locomotive Signalling References Literature Further reading Warning systems Train protection systems