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This seems rather a UK-centered and europe-centered view of signalling practise. I'm thinking about how it might be better done to reflect international variety. In the meantime, I'll probably be making some tuning changes ... --Morven 03:39, 21 Sep 2003 (UTC)
Yes you're probably right, although I did try to add a bit about American practices. Its difficult to write articles on the wikipedia, because its international, you have to try and cover the perspectives of many different parts of the world G-Man 13:44, 21 Sep 2003 (UTC)
I'll see what I can do to at least try and include information about British, American and European practice -- which probably works for most other places, since many other nations' railways buy signalling equipment from those.
There's a lot of variation in American signalling, too -- unlike most other countries where the same standard applies nationwide. Need to discuss route signalling vs. speed signalling, too -- British practice is exclusively route signalling, no speed indication is given by the signal aspect. Whereas, say, Pennsylvania Railroad position-light signals convey speed information to a degree also, and rarely do they indicate what route is set. Out here in California, most of the railroads do use color-light signals, but unlike the British form, in say ex-Southern Pacific signals, each light lens can display different colors; this is based on previous semaphore signals' lights, which change color depending on which aspect's filter is in front of the light.
Even until pretty modern times, many US railroads ran on timetable-and-train order -- the Nickel Plate and Wabash until the 1960s, for example. Many now run without many signals but using CTC and radio.
--Morven 21:13, 21 Sep 2003 (UTC)
This article is still a bit of a mish-mash of different and sometimes duplicating information (always a problem when you have multiple authors), I'll have to think of a way to make the flow of the article better and to make more sense G-Man 11:53, 26 Sep 2003 (UTC)
Something seems to have gone awry here, as there are 2 unconnected articles with differing spellings on the same topic. Railway signalling and railway signaling. Surely the railway signaling should redirect to Railway signalling, and the content be merged. John 15:00, 30 May 2004 (UTC)
Also, I cannot agree with the section on colour lights in Britain. I have read that the lights are positioned so that the red is nearest the drivers eye level, not always red at the bottom, as suggested. Can someone confirm? (I have not changed this.) John 15:00, 30 May 2004 (UTC)
There is an example of a three aspect colourlight signal at Spondon, near Derby which has the red at the top and the green at the bottom [DY410],but this is due to the signal head being on the ground not on a post. —Preceding unsigned comment added by 62.6.149.17 (talk) 03:03, 10 December 2007 (UTC)
There are numerous examples of where red is not the bottom aspect. This is usually due to infrastructure obscuring the view, or height limiting the height of the signal so the red would not otherwise be at driver's eye level. These, by their nature, are usually under structures such as bridges or in tunnels. At Birmingham New Street the signals lamps are mounted horizontally in the centre of the station - again, deep underground at this point. Co-acting signals, where a (usually) ground-mounted signal is present alongside a normally-mounted signal, the red is at the top. So in answer to your question, NO reds are not always the bottommost aspect. —Preceding unsigned comment added by Geoffmayo (talk • contribs) 16:18, 8 April 2009 (UTC)
Red lights are always placed where the driver will see them easily. Not nessecary at the bottom. Ralph Chadkirk (talk) 19:15, 22 May 2009 (UTC)
I have moved single-'l' to double-'l', and double-'l' to Railway signalling/Temp, and also with the Talk page (Talk:Railway signalling/Temp). Eventually (that is, when the functionality is available), we might want to merge the histories, too, which is why I didn't just delete the pages.
James F. (talk) 22:42, 7 Jul 2004 (UTC)
I don't know if it's just a terminology thing, but some of the information in this article is more properly known as safeworking. The first two sections of the article are Timetable operation and Timetable and train order, which are both safeworking systems that have no signals. I believe that we should either rename this article, or start a separate Safeworking article and move some of the information there. Philip J. Rayment 02:54, 12 Oct 2004 (UTC)
It seems like that would make sense. Also, the single 'l' spelling seems much more common on google. [1]vs [2]
Night Gyr 01:08, 8 Feb 2005 (UTC)
"uniquely susceptible to collision because" this seems a bit of a weird construct, you could easily argue that not being able to turn into each other is a unique way of avoiding crashes. In a non track guided vehicle you generally have to observe in all directions on a track it's forward and back.--Son of Paddy's Ego 12:02, 30 September 2005 (UTC)
I agree.--John 13:52, 30 September 2005 (UTC)
Minor criticism of the red/yellow/green explanation. Green doesn't mean "full line speed" necessarily, it means that the next signal is not red. Also yellow doesn't mean the next signal is red... often the next signal is yellow as well. (In the ABS section of the Chicago 'L', the usual sequence is red, two yellows, then green; assuming the red isn't an interlocking home signal). Anyway, I think the signal color rules are dependent on individual railways, so this could be difficult to integrate into the page. (For example, yellow on the L means that the operator must not exceed 30/35MPH, so some signals around sharp corners are never green.) Jrockway 04:45, 1 December 2005 (UTC)
There is significant overlap of content and subject matter in Railway signal and Railway signalling and I propose the content from Railway signal be merged to Railway signalling, which is a more appropriately-named article.
Please discuss at Talk:Railway signal#Proposed merge. — JonRoma 21:35, 4 February 2006 (UTC)
I am against the proposed merger. On a different note, the article could use more information regarding the many types of signalling used in the U.S.
--Wump 18:24, 15 March 2006 (UTC)
Found this article that appears to be completely isolated and unlinked - British absolute block signalling. Probably should be deleted and merged with this or linked much better with other rail signalling pages. Pickle 22:04, 7 May 2006 (UTC)
I added a cleanup tag to the article--after rereading the whole thing, I really think that it's a mishmash of a lot of good, but poorly organized, information. Based on the other comments in this talk page, I think everyone else agrees that it needs a bit of help in this area, so I hope I'm not offending anyone by tagging it. cluth 18:53, 17 August 2006 (UTC)
I've completely reordered this article without actually editing (much) of the text. I believe it flows much more smoothly now and appears to be much less focused on the signals themselves (which is really the domain of the railway signal article) and more on the operation and history of signalling/safeworking/operation methods. Before, it looked like it was a bunch of separate articles pasted together, and it really didn't flow.
There is still a bit of overlap and/or material in this article that may belong in the signals article, but it's more clearly delineated now, I believe. I hope you agree.
Also, there is still a small bit of repetitiveness in this article and it could still use some cleaning up, so I'm leaving on the cleanup tag. cluth 05:07, 18 September 2006 (UTC)
Although much has been done in recent times to better organise this article (Railway signalling) and Railway signal, there is still much that could be done.
I come at this topic as a Victorian, but have made some attempt to use more generic terminology and include systems foreign to Victoria, although my knowledge of non-Victorian systems is quite limited. As I mentioned above two years ago, what is covered in this article is known in Australia as safeworking. Whilst on one hand I accept that it is unreasonable for an Australian-specific term to be used as the overall name of this topic, on the other hand I can't see that any other term adequately covers the topic. As I mentioned there, some of what is covered by the term railway signalling has nothing to do with signals!
I also noticed that the article Railway signal begins by defining a signal as "a mechanical or electrical device that ...", but, at least in my experience, that is only one type of signal, what is known as a fixed signal. There are also hand signals, audible signals, and train (lamp) signals. Fixed signals are called that because, unlike the other ones, they are in a fixed location.
Part of the problem is a lack of a clear explanation (in the articles as they currently stand) between railway signalling and the signals themselves.
There is not a one-to-one correspondence between the two, as a number of different signal types can be used for each of the different safeworking systems.
There are already a number of articles covering this overall topic, as can be seen in category:Railway signalling, but the main ones for this discussion are Safeworking, Railway signalling, Railway signals, and Token (railway signalling).
Below I have listed a hierarchy of safeworking, the two main groups of which I've labelled safeworking systems and signals. This is my own thoughts on what I think the relationships between them are, and while meant to be fairly comprehensive is not intended to be exhaustive.
--Signal127 (talk) 05:17, 10 July 2013 (UTC)This section on safeworking/signals makes sense to me. In my attempt to understand New Zealand Signalling I wrote the following: "The safe operation of a railway depends both on the signalling (i.e. the hardware) and the safeworking rules (the software) that define how the hardware is used." This may not be strictly correct but it helped me understand the subject. The rules (software) applying to a particular signal can be changed by issuing a bulletin which changes the classification of a signal. I know of an example where a Departure signal temporarily became a Starting signal so that it could be passed at stop without any paperwork. See http://valleysignals.org.nz/pukeruabay/pkb.html. On my web site I also said: "Two systems are used in New Zealand - Automatic signalling (with several variations) and procedural (in non-track circuited territory - points indicators/signals at crossing locations only).". To see how I use this to explain NZ signalling/safeworking go to http://valleysignals.org.nz/hvsignals/signallingoverview.html.
"Signalling" is probably the wrong term to use when trying to explain railway operations. I admit that when I started my web site over ten years ago I used the term "Signalling" in the title because I did not know any better. Maybe the wiki page needs a different title but I am not sure what it should be.
Because it is difficult to put a bulleted list in a table, I have repeated the various topics of the first list in a second list which shows in which article each topic is currently covered. It can be seen that some topics are not covered or inadequately covered. It also helps demonstrate how much of the overall topic each of the main articles cover, and may help to better organise those articles. According to the hierarchy below, some topics (e.g. detonators) are in the wrong article. I have not gone through every article thoroughly, so I may have missed bits, and any corrections and comments are welcome. Feel free to directly modify (but not reorganise) the lists if appropriate.
Philip J. Rayment 11:20, 18 September 2006 (UTC)
Topic | Article(s) currently covering topic |
---|---|
SAFEWORKING | Safeworking, Railway signalling |
Safeworking systems | Safeworking, Railway signalling |
One engine in steam | Safeworking |
Timetable working | Safeworking, Railway signalling |
Train Order working | Safeworking, Railway signalling |
Token working | Token (railway signalling) |
Staff & Ticket | Token (railway signalling), Safeworking (placeholder only) |
Electric Staff | Token (railway signalling) (briefly) |
Miniature Electric Staff | Safeworking (placeholder only) |
Radio Electronic Token Block | Radio Electronic Token Block |
Pilot working | Token (railway signalling) (briefly) |
Manual Block working | Railway signalling, British absolute block signalling |
Automatic Block working | Railway signalling, Automatic Train Control (axle counters not mentioned in either article) |
Moving Block | Railway signalling |
Signals | Railway signal |
Hand signals | not covered |
Train signals | not covered except for a mention of tail signals in Railway signalling |
Audible signals | not covered |
Train whistles | not covered |
Detonators/Torpedoes | Railway signalling |
Fixed signals | Railway signalling (mention only, not defined) |
Semaphore signals | Railway signal |
Colour light signals | Railway signal |
Position light signals | Railway signal |
In-cab signals | Railway signalling, Cab signalling |
We also need to address the different systems of signal meaning. I can address NA "speed signalling" practice, whose diversity fortunately requires a general approach. The other types of system need to be addressed without succumbing to the temptation to spell out every little variation as if it were of major importance. Right now, the articles on British practice seem to have a lot of trouble seeing the forest for the trees. For instance, the articles on home signal and distant signal probably ought to go away. The terms are used universally in block systems and interlocking protection, and there's really no way of writing a stand-alone article on either that is accurate and that works in all contexts. Mangoe 16:10, 18 September 2006 (UTC)
Discussion of the American systems here would be limited to how the signals are interpreted, with the control details pushed off into separate articles (or earlier sections). I suspect that the UK discussions would divvy up content differently, but the main thing is to avoid burdening this article with variants and exceptional examples, which would be better placed in some sort of UK signalling article. Mangoe 17:39, 20 September 2006 (UTC)
Just trying to sort out serveral articles on signalmen, and would be greatful if someone who knows a little more about the subject could make a half decent stub of signalman (rail). Renski 15:53, 20 September 2006 (UTC)
This article should aim to explain the overall principles of railway signalling that apply throughout the world, rather than mentioning details specific to any particular country (for which there may be separate articles). The huge section headed "Modern signaling in the U.S." is just a copy of what is written in the article North American railway signaling, the latter being the proper place for that information. I therefore propose to delete that whole section from this article as a first step to improving it. Any comments? Signalhead 19:30, 3 January 2007 (UTC)
Since there are so many different discussions on this subject involving so many different articles, I've started the discussion over on the Operations Task Force talk page, which seems like a better place to see the big picture. I've put a list of articles with significant overlap over there, and perhaps those of us interested in trying to figure this out should join the Operations Task Force so we can work together instead of everyone being on different wavelengths.
I wonder if this article (railway signalling) should just go away completely and all of the content be merged into the various national articles (e.g. Safeworking in Australia, Railway signalling in the United Kingdom, Railroad Methods of Operation in North America, etc.--we'd need to do some name changes on some of these articles, which I also propose).
Thoughts? cluth 02:22, 8 April 2007 (UTC)
Yes do it.
The introduction is also very confusing to an uninformed reader. And if accurate timekeeping was so important in the US, why did it take until 1891 to do it. And who is the general time inspector, Ohio?
Afterbrunel 13:06, 31 July 2007 (UTC)
The article states "Although signals vary widely between countries, and even between railways within a given country, ..."
Then there are separate wiki pages for individual countries.
I would be interested in seeing a discussion of why different countries have created different systems, and what advantages each one is attributed to have.
I am sure some systems are created as responses to percieved deficiencies in earlier systems of neighbouring countries.
195.24.29.51 12:31, 16 August 2007 (UTC)
I'm not an expert (just an individual with a certian level of professional interest) but can this section really be right about a green light over a red light indicating that the next signal is red? Wherever a red light is shown, it surely has to mean "stop here" - making any exception to this would make red lights elsewhere open to interpretation by the driver. And why bother with green over red, when yellow indicates that the next signal is red? viking10000 14:08; 15 Aug 2007 (UTC)
I don't think this article makes the difference between ATP and In-cab signalling clear, especially when it talks about ATP being used in fog. ATP is typically a lower safety-level device than in-cab signalling. It is designed to replace a second driver in protecting the train rather than allowing operation in the absence of visible track-side signalling. For example, an ATP system might be SIL2 and apply the emergency brakes when the train moves out of established parameters (speed, movement authority, etc). The driver must still be aware of track-side signals and drive the train correctly in order to avoid the emergency brake from applying. Noone should die if the ATP gets it wrong. The driver is still responsible for following the signals.
An In-cab signalling might be SIL4, and thus would allow the train to be operated in fog and on railways with different signalling conventions to what the driver is trained for. It can replace, rather than merely supplement the track-side signals. A malfunctioning in-cab signal could allow a train to be driven into danger, and there would be nothing the driver could do to anticipate that danger. In the absence of a second driver in-cab signalling can provide train protection capabilities that less drastic braking solutions than ATP, due to its higher safety level. —Preceding unsigned comment added by FuzzyBSc (talk • contribs) 06:09, 3 October 2007 (UTC)
I think Signalhead's edit of 8 September 2008 is unnecessarily restrictive. Double yellow signals do exist so they should be mentioned somewhere. Biscuittin (talk) 09:14, 9 September 2008 (UTC)
I do not fully understand this topic and am not able to optimally place this image. I suggest someone who has a better understanding of the topic do so.--TonyTheTiger (T/C/BIO/WP:CHICAGO/WP:FOUR) 04:54, 11 June 2010 (UTC)
I'm operating under such a system and having a additional yellow light by the green light (Hp2 in H/V Signalling System restricing speed to 40 km/h instead of full speed) is the same as having a route indicator. I other systems (Germany Ks, Swiss System N a number just shows the allow restricted speed for the diverting route - also just one additional signal lamp in copamre with the route indicator) I don't see what it requires a far greater range of aspects. So i'm not very happy with this sentence. Since i'm not native english speaking, i don't make any corrections to avoid mistakes. --79.199.43.50 (talk) 17:30, 12 February 2011 (UTC)
The norm of the 19"-rack has been developed for / with railway signalling says that article. Should possibly be mentioned here. --Helium4 (talk) 13:03, 11 February 2012 (UTC)
Several previous comments suggest that the page is a mish-mash, and I agree. We need to separate out the issue of signalling -- which I take top mean the procedure to give messages to control train movements to prevent collision, from a lot of the mechanics.
The contrast between UK and US + Australian practice is also very stark, and fundamentally different and conflicting assumptions are made.
I was also surprised not to see "Time interval working" described (as a historical method) and not much about single line operation.Afterbrunel (talk) 06:48, 22 September 2012 (UTC)
The main problem with a coherent description of railway signalling is the following: Any literature on railway signalling from one of the three large "cultures" (Middle Europe, UK, and US) did and does not (or only very very very rarely) look into the other two cultures (and the same seems true of most people I know). Therefore, extracting the worldwide principles (which do exists; e.g., block signalling; distinction between train and shunting signalling; etc.etc.) always borders on "original research", which is not acceptable in WP.
Currently, I know of only one book that transgresses these divides, namely Jörn Pachl's "Railway Operation and Control". Maybe we should try to excerpt that book, or at least follow its principal concepts. There are a few mostly dormant and out-of-date web sites that tried at least to collect many signalling practices, but they can be a starting point at best. Another candidate might be Theeg, G.; Vlasenko, S., Railway Signalling & Interlocking - International Compendium, Eurailpress, 2009!). Maybe we should despair - and create unconnected pages for lots of countries, probably only in their own language (Argentina only needs a Spanish page, for example)- and that's it.
But do we really want this? --haraldmmueller 19:15, 7 September 2014 (UTC) — Preceding unsigned comment added by Haraldmmueller (talk • contribs)
This article could use a section on railroad hand signals. Turrit hugger (talk) 12:41, 21 September 2021 (UTC)
There is nothing here or at railway signal about approach lighting. --User:Haraldmmueller 08:10, 28 May 2022 (UTC)
I was looking at a magazine article today which mentioned how code lines running on poles like telegraph and telephone lines are rarely used any more. Instead most updated communications systems for railroad signals and other purposes have been buried. But I don't see anywhere on Wikipedia where "Code lines" could redirect. It may be the details belong in this article.— Vchimpanzee • talk • contributions • 17:22, 17 November 2022 (UTC)