Talk:25 kV AC railway electrification

message: Yes, "mains" is not a term commonly used in English in North America. However, the term "household electricity" is not a suitable alternate term in this context, even though it might be in some others, since electrified railway lines are not household. If Americans don't understand the word "mains", pick a better alternate term. --144.136.125.106 06:47, 24 December 2005 (UTC)
thread_title:  Use of term "mains" 

message: "Two isolated freight lines passing through desert country had double 25 kV to 50 kV to further reduce energy losses in their transmission lines."
Where were these lines?  Myrtone (the strict Australian wikipedian)(talk)Contrubitions
: One is in the US, the Black River coal line, IIRC.
: The other is the Sanhalda iron ore line in South Africa. Tabletop 06:26, 29 October 2006 (UTC)
replies: text: I'm positive i remember reading in a book (sadly the book wasn't mine and i don't have access to it now, nor do i remember the exact title) that there was one in australia too. Plugwash 14:04, 29 October 2006 (UTC)
thread_title:  50 kv AC 

message: I think we are getting close to a deal! We do have a page called Overhead lines and 25kV AC is a subset of that form of railway electrification system.  If we moved the material on this article across to the Overhead lines article and renamed it to "Railway Electrification - Overhead Line Systems" (or something along those lines) then I would be happy to change the articles that link to this page so that they linked to the renamed overhead lines page.  This article could then (with everyones agreement) be proposed for deletion (by whatever means suits people).  If we can convince people that no information will be lost, then perhaps we can "close the deal".  The information on 50kV railways could also be transferred to that page (I have it saved). In time, if enough material was placed on the renamed overhead lines page then a new article (or a stub) could be created. ALECTRIC451 22:20, 17 January 2007 (UTC)
thread_title:  A Proposal

message: OK i know this page is bad, and we're *slowly* working on improving all Wikipedia railway electrification articles. however until thats done and all the info on this page (and its talk page) is superfluous then we can go through the proper motions and propose deletion, not just wipe it. Pickle 02:27, 11 February 2007 (UTC)
replies: text: Good revert. As one of the opponents of this page, even I was annoyed to see it removed. I wish that people who are not part of the Wiki Trains Project would post their intentions on the talk page BEFORE taking unilateral action.  Okay, I will make improvements to this page in order to protect it against deletion/redirection, but on the understanding that we rename it at some point. I hate the name of this page, but its inclusion is beyond question. --ALECTRIC451 18:39, 11 February 2007 (UTC)
replies: text: Eaxctly there are lots of things needing doing and this page's continued existance with its current name and contents is still in doubt but proper talk, et al that is meant to happen didn't take place Pickle 21:15, 11 February 2007 (UTC)
replies: text:  Theres a lot that could be done indeed.  Railway electrification system is reasonably well written, and its daughter article overhead line is where the info in this article belongs.  Overhead line lacks the electrical engineering content.  This article's content needs to be merged into it, and so as not to lose any links a redirect can be made.--Oldboltonian (talk) 20:55, 29 April 2019 (UTC)
thread_title:  redirect to [[Railway electrification system]] 

message: a possible and possibly common thing done with 25 kV overhead wires is having an opposite phase 25 kV line also, which means a total of 50 kV between it and the normal wire. this may be an extra wire above the ground, which then serves 2 purposes:
- reduce electromagnetic interference
- be used together with booster transformers to reach a longer distance with fewer substations.
this is used in the netherlands for 25 kV overhead wires, and possibly elsewhere (look for the presence of an extra, separately insulated, wire in an overhead line system)
this is explained on the dutch wikipedia:
http://nl.wikipedia.org/wiki/Spoorwegtransformator
Bewareircd (talk) 00:43, 27 November 2008 (UTC)
replies: text: See also: Central_Organization_for_Railway_Electrification#2_x_25_KV_System and Amtrak's_60_Hz_traction_power_system#Substations. Biscuittin (talk) 21:00, 23 November 2011 (UTC)
replies: text: I have added a new section "2 x 25 kV autotransformer system". Biscuittin (talk) 22:53, 23 November 2011 (UTC)
thread_title:  mention opposite phase wire used 

message: Is it true that all or most 25 kV systems use an overhead caternary system of electricity delivery?  If so, we should mention this in the opening paragraph.  I would add it, but I'm not sure what is the accurate summary of affairs.  All the 25 kV systems i know about use overhead caternary, but I'm by no means an expert.  Cheers —fudoreaper (talk) 09:07, 13 February 2009 (UTC)
replies: text: For high voltages an overhead wire is always used due to the great clearances required. A 3rd rail cannot be used with high voltages because sparking and leakage would be too great. 82.139.114.136 (talk) 12:53, 28 May 2012 (UTC)
thread_title:  In an overhead caternary always used? 

message: The advantage of using 25 kV AC with 50 Hz respectively 60 Hz is that the current for the catenary can be got easily from the power grid. Nevertheless for the supply of some TGV lines in France single phase AC power lines were built, as some pictures on http://www.justmystage.com/home/overheadtml/france1.html show. Why?  —Preceding unsigned comment added by 91.46.242.193 (talk) 16:45, 6 June 2009 (UTC)
replies: text: Three phase power systems work best when the load on each phase is roughly equal.  This is hard to achieve on railroad electrification systems and the French may have decided it was better to transmit single phase AC for some segments.--agr (talk) 17:10, 19 July 2009 (UTC)
replies: text: Single phase electricity will hardly ever be created due to the fact the power deliverance is sinusoidal and not continuous. I expect the single phase grid in France comes from a three phase grid somewhere, but is distributed from a single point. To prevent imbalance VAR compensator's are sometimes used. 82.139.114.136 (talk) 12:45, 28 May 2012 (UTC)
thread_title:  Single phase powerlines when 25 kV AC is used 

message: narrow gauge with 25kV AC: more disadvantage?
narrow gauge with 25kV AC in snow and/or steep grade: much more disadvantage?
121.102.47.215 (talk) 05:53, 13 March 2010 (UTC)
replies: text: What is the relationship between the gauge and the disadvantages of 25kV AC?--Bk1 168 (talk) 07:53, 28 May 2010 (UTC)
replies: text: Usually narrow gauge tracks are built in locations where there is only a small clearance and a lot of sharp bends. Especially in these conditions the construction of a high-voltage overhead wire can be a big pain in the ass. High voltages are in use on narrow gauge tracks though in Switzerland (15 kV 16 2/3 Hz). 82.139.114.136 (talk) 12:51, 28 May 2012 (UTC)
thread_title:  Disadvantages 

message: UIC standard voldages:
DC voltage: 3 kV
AC voltage: 25 kV (50 or 60 Hz)
121.102.47.39 (talk) 12:02, 22 May 2010 (UTC)
thread_title:  UIC standard 

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thread_title:  External links modified 

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thread_title:  External links modified 

message: The text of this says Periodic autotransformers divert the return current from the neutral rail, step it up, and send it along the feeder line. However, this is not true.
What happens is that the autotransformer splits the return current and only half goes to the feeder, the other half goes to the overhead line. This means that in the overhead line, half the current is supplied from the supply transformer connection, the other half is supplied by the autotransformer. The supply transformer drives half the current via the feeder line, in antiphase to the overhead line, which is actually the half of the return current in the autotransformer which goes to the feeder.
The requirement for ampere turns balance on the autotransformer requires that the return current is split to go half and half to the overhead line and to the feeder.
Now, I am very wary of altering the article, because some Wikinazi is likely to come along, demand a citation, at which point, I will point to the Wikipedia article on autotransformers, which has informed my understanding of this. And I will have to explain in some detail why the ampere turn balance requirement works this way for 2 * 25kV systems and even justify ampere turn balance on transformers, at which point, someone who does not understand something like "magnetising current" will say "ah but there is no real ampere turns balance" and then I explain this and the whole thing is ruled out of order as being original research, any change I make to the article is reverted and the article stays wrong.
78.33.185.122 (talk) 12:28, 29 April 2020 (UTC)
thread_title:  2 x 25 kV autotransformer system - error 

message: There's an interesting tweet today, here, by the current author of a book on OLE saying that the explanation of autotransformers given in the book has been wrong for years and giving the version that will be included in a new edition. Perhaps someone with better understanding than mine could check to see if anything in this article needs changing. --Cavrdg (talk) 20:16, 3 August 2021 (UTC)
thread_title: Tweet by author

message: This article has not been focusing on 25Kv AC per se, but rather on the use of utility frequency power supply, which is typically 50 or 60Hz. All systems mentioned here use utility frequency, but not necessarily 25Kv. As a result, I suggest that this page be moved to a more appropriate title. Some possible ideas: utility frequency railway electrification, 50Hz AC railway electrification, high frequency AC railway electrification etc. Any thoughts? Mako001 (C)  (T)  🇺🇦 02:10, 11 September 2022 (UTC)
thread_title:  Move suggestion 

message: The utility frequency in Saudi Arabia is 60 Hz, while this article says the Haramain high-speed railway uses 25 kV 50 Hz. Is it an error, or is there a dedicated facility generating electricity at 50 Hz solely for the Haramain high-speed railway? Aliew (talk) 21:31, 5 January 2023 (UTC)
thread_title:  Saudi Arabia's Haramain high-speed railway