A system to provide protection against the consequences of Signals being
passed at DangerAn indication given by a Signal to stop. More and overspeed protection at certain speed restrictions.
Loops are laid in the track which emit specific frequencies such as to limit
the speed of a train (Overspeed Sensor System – OSSAn Overspeed Sensor System as applied to a TPWS. More) and stop a train
(TrainstopA trackside device which may be controlled to initiate an emergency brake application on any train passing it. More System – TSSTrainstop System as applied by TPWS. More).