Editing Automatic Warning System (section)

=== Expansion of AWS application ===
* From 1971, an AWS permanent magnet was fitted ahead of the [[UK railway signalling#Permissible speed indicators|warning indicator]] where the permissible speed of a line dropped by more than a third.<ref>{{cite web| title =Master Rulebook: Signals, hand signals, indicators and signs handbook. Section 7.2 "Warning indicators"| url =https://www.rssb.co.uk/rgs/rulebooks/GERM8000-master-module%20Iss%201.pdf| publisher =Network Rail| access-date =2017-03-07| archive-date =10 August 2018| archive-url =https://web.archive.org/web/20180810143338/https://www.rssb.co.uk/rgs/rulebooks/GERM8000-master-module%20Iss%201.pdf| url-status =dead}}</ref> This was a recommendation of the inquiry into the [[Rail accidents at Morpeth#1969 derailment|derailment at Morpeth]] on 7 May 1969.
* From 1977, a portable AWS permanent magnet was fitted ahead of the warning board on the approach to [[UK railway signalling#Speed restrictions|temporary speed restrictions]] (TSRs). This was a recommendation of the inquiry into the [[Nuneaton rail crash|derailment at Nuneaton]] on 6 June 1975, which occurred when the driver missed a TSR warning board due to its lights being extinguished.
* From 1990, AWS permanent magnets were installed immediately ahead of certain 'high risk' stop signals, as a [[Signal passed at danger|SPAD]] mitigation measure. This additional AWS magnet was suppressed when the associated signal showed a 'proceed' aspect. Since the introduction of the [[Train Protection & Warning System]] (TPWS) it is no longer current practice to use AWS for this purpose. [[Signal passed at danger#Collision prevention systems|SPAD indicators]] were also used.