Editing Automatic Warning System (section)

=== Additional functions ===
AWS was later extended to give warnings for;<ref name="Awsrules 1.4">{{cite web| title =AWS & TPWS Handbook: Section 1.4 "AWS indications and their meanings"| url =https://www.rssb.co.uk/rgs/rulebooks/RS522%20Iss%203.pdf| publisher =RSSB| access-date =2018-09-24| archive-date =5 December 2016| archive-url =https://web.archive.org/web/20161205171951/http://rssb.co.uk/rgs/rulebooks/RS522| url-status =dead}}</ref>

* A [[UK railway signalling#Running signals|colour light signal]] displaying a double yellow (steady or flashing), single yellow or red aspect
* A [[UK railway signalling#Speed indicators|reduction in permissible speed]]
* A [[UK railway signalling#Speed restrictions|temporary or emergency speed restriction]]
* An [[Level crossings in the United Kingdom#Types of crossing|automatic barrier crossing locally monitored]] (ABCL), an [[Level crossings in the United Kingdom#Types of crossing|automatic open crossing locally monitored]] (AOCL), or an [[Level crossings in the United Kingdom#Types of crossing|open crossing]] (OC).
AWS was based on a 1930 system developed by Alfred Ernest Hudd<ref name=GG>{{Cite web|url=https://www.gracesguide.co.uk/Alfred_Ernest_Hudd|title=Alfred Ernest Hudd - Graces Guide|website=www.gracesguide.co.uk|language=en|access-date=2019-08-06}}</ref> and marketed as the "Strowger-Hudd" system. An earlier contact system, installed on the [[Great Western Railway]] since 1906 and known as [[Automatic train control#United Kingdom|automatic train control]] (ATC), was gradually supplanted by AWS within the [[Western Region of British Railways]].