Talk:Track circuit

message: This article is duplicated by Track circuits.
Tabletop 03:30, 20 Jun 2005 (UTC)
replies: text: They do indeed cover the same topic.  I've added  and  to both articles suggesting that this article be the final destination (following WP:MOS for the article title). slambo 18:17, 17 October 2005 (UTC)

text: Merge --Soumyasch 06:04, 25 February 2006 (UTC)

text: Merge to Track circuit--Lordkinbote 09:32, 7 March 2006 (UTC)

text: Merge I agree that they should be merged, however I've always heard the term Track circuits used in industry and would suggest flipping the merge-to and merge-from tags.  Skabat169 14:29, 17 April 2006 (UTC)

text: Obvious merge — Omegatron 16:20, 23 April 2006 (UTC)

text: Merge - Birdhurst 00:29, 26 April 2006 (UTC)

text: It seems this has already been done; therefore, the above discussion should be archived. 69.140.164.142 05:14, 6 April 2007 (UTC)
thread_title:  Merge from [[track circuits]] 

message: Yet another duplication of efforts. Slambo (Speak) 13:28, 29 August 2006 (UTC)
thread_title:  Merge from [[Rail circuits]] 

message: This time it's poor shunting, which is simply one bit under "circuit failures".
On a related note: we seem to be trying to grow a list of accidents. I can see leaving the Cowan rail crash as it is an example of a failure mode, though I would incorporate it into the main text rather than letting it sit out in a list. Listing accidents which the presence of track circuits would have prevented strikes me as dubious (since it could be expanded to encompass every 19th century collision) and speculative. Mangoe 13:53, 29 September 2006 (UTC)
replies: text: I agree.  I was just looking at poor shunting myself and wondering why it existed.  I was also amused that it says that poor shunting is something that affects railroad signalling in North America and the UK, then provides one real-life example—from Australia!  Philip J. Rayment 13:58, 29 September 2006 (UTC)
thread_title:  Another merge 

message: Having worked on railroads in several areas of the world (in my early days I was a signal maintainer), the only term I have consistently heard to describe a track circuit is, in fact, track circuit.  All information regarding track circuits should, in my opinion, be coalesced into a single article titled Track Circuits.
Also, the article, as presently written, confuses signal operation with track circuit operation, which are mutually independent functions.  All a track circuit does is indicate the presence or absence of a train in a given stretch of track.  The use of that information has no relationship to the track circuit itself (in fact, most designs carefully isolate a track circuit from what it controls to maximize reliability).  A track circuit could control block signals, operate grade crossing signals, set up first-come, first-served interlocking, turn on station platform lights and annunciate the approach of a train to passengers waiting in a station...you get my drift.
BDD 22:15, 23 February 2007 (UTC)
thread_title:  Track circuit 

message: How badly are track circuits affected by snow and ice (compared to say sand and rust)?
Tabletop (talk) 11:43, 25 December 2008 (UTC)
replies: text: Snow and ice are seldom problems due to the unit loading that occurs at the interface of wheel and rail—the snow and/or ice will be liquified and force out.  Rust can be a problem and may result in failure to shunt, creating a potentially deadly condition.
Bigdumbdinosaur (talk) 18:22, 9 January 2009 (UTC)
thread_title:  Snow and Ice? 

message: "Track circuit relays are specially designed to reduce the chance of wrong side failures.  They might for example have carbon-silver contacts to reduce the likelihood of the wrong contacts welding shut after power surges and lightning strikes."
:: In French relay practice, IIRC, they use silver-silver contacts.
- Does that really need to be stated in this article? In British practice, all relays in vital signalling circuits have carbon-silver contacts to minimise risk of wrong side failure.–Signalhead < T > 17:55, 29 May 2009 (UTC)
thread_title:  Relays 

message: What does this mean?
<quote>In some countries, AC-immune DC track circuits are used on AC electrified lines. One method provides 5 V DC to the rails, one of the rails being the traction return and the other being the signal rail. When a relay is energised and attached to the track, normal voltage is 5 V DC. When there is a break in the circuit and there is no train, the voltage rises to 9 V DC which provides a very good means for fault finding. This system filters out the voltage induced in the rails from the overhead lines.</quote>
9 volts and 5 volts relative to what? How is the circut made? 86.141.233.251 (talk) 13:21, 16 April 2012 (UTC)
replies: text: Also I would think it preferable for both tracks to carry traction return current to reduce losses.
The track circuit block sections would be isolated with impedance bonds for which Wikipedia has no article 86.141.233.251 (talk) 16:18, 16 April 2012 (UTC)
thread_title: Circuits under electrification

message: I'm an electrical engineer, but I can't make sense of this section. It immediately jumps into details of specific commercial products after an inadequate introduction. Somebody who understands this topic should write a longer, clearer introduction followed by more explanation and less jargon. I came here to learn, so I'm not the one. This is written more like a technical presentation than an encyclopedia article. Will any uninformed general reader know what "This can be extended to 2200 m with compensating capacitors." means? Robsavoie (talk) 20:07, 5 June 2011 (UTC)
replies: text: I have similar problems.
To prevent the audio signal from one section passing into an adjacent section, a simple tuned circuit is connected across the rails at the section boundary
How does it do this? 86.141.233.251 (talk) 13:21, 16 April 2012 (UTC)
thread_title:  Jointless tracks circuits is confusing 

message: Frequencies of the Aster SF 15 type track circuit are 1700 Hz and 2300 Hz on one track and 2000 Hz and 2600 Hz on the other. 
What track and what other?
The lack of modulation can lead to availability problems as well as making the signalling safety case difficult to produce. 
What? Why?
To simplify traction pack design in locomotives, many track circuit manufacturers now transmit a unique code from the transmitter to the receiver. 
Whay would you need a traction pack in the loco if all the system is for is inform the signaller of the presence or absence of a train in the section.?
I think that's all for now. THanks 86.141.233.251 (talk) 13:21, 16 April 2012 (UTC)
thread_title: Some popular AF track circuits used in the UK

message: If this exists anywhere in the world, I suspect it is rare. One of the basic principles of point locking in all the countries I've worked is to disable movement if the track section over it is occupied - thus dropping the track if the points are reverse would lock them permanently! At the very least, citations are required to make this less dubious.  — Preceding unsigned comment added by 108.23.115.151 (talk) 20:57, 21 September 2015 (UTC)
replies: text: If this dubious info is not true, then I propose a Db-G3 eval.Lomrjyo 03:01, 20 May 2018 (UTC)
thread_title: Siding Turnout

message: I’ve read the CTSB report on this wreck.  No blame for the wreck was assigned to signalling and/or track circuits.  This wreck should not be in the list of wrecks attributable to signalling failure.
:216.152.18.132 (talk) 08:04, 11 March 2023 (UTC)
replies: text: The line was unsignaled so yeah.Sturmovik (talk) 13:25, 15 March 2023 (UTC)
thread_title:  Lac-Mégantic rail disaster 

message: The reference to ‘isolated’ track circuits ought to use a different term (individual?) In CIRCUITS UNDER ELECTRIFICATION paragraph 4 Andyeff (talk) 12:57, 2 February 2024 (UTC)
thread_title:  Poor terminology