Talk:Cab signalling

message: The article currently claims that the maximum speed without cab signals is 80mph, but I had thought that the effective speed limits for passenger trains in the US is typically 79mph.  This article ought to cite a source on the speed limit.  JNW2 20:54, 2 December 2007 (UTC)
thread_title: Maximum speed without cab signals

message: My understanding has been that exceeding the speed limit that's somewhere around 79 or 80mph requires that cab signals be present, but does not actually require automatic stop equipment (though once you have gone to the trouble of installing cab signals, there may be little point in not having the automatic stop equipment).  JNW2 20:54, 2 December 2007 (UTC)
thread_title: Automatic stop requirements

message: The article currently states "Cab signaling in the United States was driven by a 1922 ruling by the Interstate Commerce Commission that trains would be limited to a speed not exceeding 80mph without some form of automatic train stop."  However, that limit was not actually imposed until 1947.  In 1922, the Interstate Commerce Commission only required some form of automatic train control installed in one division.
One reference to the history available on the web is "Transportation Research Circular" Number E-C085, Januaray 2006 "Railroad Operational Safety", Status and Researchh Needs, published by the Transportation Research Board of the National Academies, available at http://www.trb.org/publications/circulars/ec085.pdf 
On page 27: "The Signal Inspection Law of 1920 amended a 1910 act. With this amendment, on June 13, 1922, the ICC issued an order requiring 49 railroads to install by January 1, 1925, over one full passenger division, systems for a form of automatic train control."
In the next paragraph: "On June 17, 1947, the ICC issued an order that required lines with speeds of 80 mph or greater to use an automatic train stop (ATS), or a socalled ATC, or an ACS (70)."  —Preceding unsigned comment added by GregGritton (talk • contribs) 23:11, 13 April 2008 (UTC)
replies: text: As I understood it the 80mph limit was set to take effect in the future from some previous time as a further effort to spur ATS adoption.  The railroads had many years of warning to implement the safety systems.  It was probably set in the 1930's and took effect after the war.Sturmovik (talk) 03:57, 19 April 2008 (UTC)
thread_title:  The "not exceeding 80mph" limit was imposed in 1947. 

message: There are a number of references in the article to the Victoria line system using a variation of "the power-frequency coded track circuit system developed by the Pennsylvania Railroad (PRR)" this information dated from 2008. The entire line has subsequently been resignalled. I don't know enough about signals to know if the new systems is also a variation of the above, but from this quote "Westinghouse Rail Systems is installing Westrace electronic interlockings with Distance-To-Go Radio to replace the legacy ATO and ATP systems on the Victoria Line, which operate via rail-borne coded signals. " from this Railway Gazette article seems to suggest that it is not and the article needs to be updated. Could someone more knowledgeable than I on matters of signalling please update this information. Thanks MrWeeble Talk Brit tv 17:44, 21 December 2012 (UTC)
thread_title:  Victoria Line