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Here are some other random facts and/or edits I was planning on working in, but I ran out of steam (no pun intended).
I know I'm barely making sense here, but I figured I'd spew all this info out before I forget it all. If anyone can take the above info and run with it, feel free--otherwise I will hopefully not forget to come back and try to straighten this all out. Check out this link, which is linked to at the bottom of the article, and see if you can pry any ideas from there (without performing a copyvio, of course). A quick glance at that page seems to indicate that it's well-written. Also see the companion page discussing specifically North American brake systems.
cluth 05:26, 8 September 2006 (UTC), (who really shouldn't be typing right now)
Not to be overly pedantic about it, but "trainline" is a single word—not "train line." However, what is being referred to in the article as a "train line" is in reality the "brake pipe," which is two words. :-) Generally speaking (in North America) the term "trainline" usually refers to electrical interconnections. I've heard the usage "trainline air" to refer to locomotive main reservoir pressure being conveyed to cars (e.g., for dual pipe brake systems, pneumatic door operators, etc.), but never for the brake pipe itself. We should try to keep the terminology in line with customary railroad practice.
BDD 19:23, 7 March 2007 (UTC)
Just to add some words, I have here a brake supply drawing from a Erie built GE 85 Ton shunter: the air line are named as "Brake Pipe", "Main Pipe" and "Main Reservoir Pipe". -- Hosdo ( talk) 15:51, 16 October 2012 (UTC)
In the UK, "train line" is commonly understood to mean a railway route (e.g. between two cities: "the train line from London to Bristol"). If "break pipe" is an equally suitable terms to train line then perhaps it should be used instead (I'm not a specialist in this area).
Again in the UK, the "trainline" is often the name of the electrical feed used in locomotive multiple working. It means that a driver's desk has been switched on and results in power being applied to the electrical machines - exhausters, compressors etc.
Again, I'm not a train engineer but I do travel regularly by train in the UK. I've never been aware of an engineer connecting pneumatic pipes between trains as two trains are combined into one (or vice versa). Do UK trains use a pneumatic line, or do they tend to have electronically controlled brakes? This article is written to imply that all train brakes are pneumatically controlled (which may well be the case). Thelem 02:52, 10 March 2007 (UTC)
Here in the USA, we occasionally use the word "line" to refer to a railroad, although seldom with the word train. In North America, any railroader, upon hearing the word "trainline," will immediately think about electrical interconnections that run the length of the train. The same term has the same meaning in electrically propelled subway or elevated trains as used in urban transit systems.
Cables that link the trainlines of one car to another (or one locomotive to another) are often called "jumpers," such as the 27-pin MU cables that join locomotive control systems together. Similar jumpers are used to convey hotel (head end) electrical power back to passenger cars, link automatic door control systems together, and so forth. In other words, most railroaders, at least here in the "New World," will immediately think electrical when trainline is mentioned.
I can't recall ever having heard the brake pipe being called anything but a brake pipe, as it has a very specific role in the overall control of the train. If another pipe passes locomotive main reservoir air pressure back to the cars it is called "trainline air" and is understood to be air at relatively constant pressure (the brake pipe pressure, of course, varies according to how the engineer manipulates the automatic brake). By the way, air connections between locomotives are generally called MU hoses—their function relates to locomotive control and not general train control.
Regarding what type of braking system may be used, it depends on your definition of "train." If you include subway or elevated trains used in metropolitan rapid transit systems (what we Yanks often refer to as the "el" or "L"—the former a New York City term, the latter a Chicago term) into the "train" definition, then no, not all trains use pneumatic braking. For example, the L trains in Chicago use a combination of dynamic (rheostatic) and electromechanical braking and, in fact, the dynamic system is the primary means of reducing speed. There's also an auxiliary track brake that may be used in an emergency if the rails are slippery.
As a practical matter, pneumatic braking styled after Westinghouse's invention is nearly universal on locomotive-hauled trains due to the weight involved and the relative simplicity of the system—especially important if there are a lot of cars. I'm not familiar with the technical details of how UK electric trains are braked, but I suspect that, again due to weight, as well as speed, it is most likely an electro-pneumatic system.
As for coupling up air hoses, the trains on which you normally travel are designed so that all interconnections are built into the coupling mechanism, obviating the need for anyone to get down between cars and connect hoses. This arrangement is very common with electrically powered transit vehicles and is nearly universal on North American rapid transit and light rail (tram or street car) applications.
BDD 05:35, 16 March 2007 (UTC)
Within the global railway industry, the term 'trainline' (one word) is internationally accepted and understood. It refers to a connection (pneumatic or electrical) that is carried between vehicles in a train. It does not refer to a 'rail line' (a line of railway) as has been suggested here. The use of the word 'train' where the writer actually means 'rail' or 'railway' is like a father telling a young child "Look at the big train" when they are pointing to a locomotive. It's OK for the kids but it's Thomas The Tank Engine stuff... it's naff and it has no place in in this section of Wikipedia. 203.153.205.105 ( talk) 10:38, 12 August 2013 (UTC)
Something on the history/development of railway brakes would be of interest... TREKphiler hit me ♠ 18:43, 4 August 2008 (UTC)
This is a bit out of date:
Electro-pneumatic brakes are currently in testing in North America and South Africa in captive service ore and coal trains.
Should be Electronically controlled pneumatic brakes, which by 2012 are going into service. Tabletop ( talk) 22:56, 9 August 2012 (UTC)
See Longest trains
Tabletop ( talk) 11:16, 1 November 2008 (UTC)
I noticed the recent addition of the Westinghouse HSC electro-pneumatic braking system to the article, but the edits missed a few key advantages of this system. Due to the fact that the "straight-air pipe" is charged and discharged by solenoid valves on each and every car of a train with HSC braking (air supplied by aux reservoirs on the cars, charged from the trainline) , it can react much quicker than the standard airbrake system (charged and discharged only at the controlling locomotive, and slightly delayed by the valving). The EP system also allows a much more graduated release than is available via the trainline (with 24RL or D-22L locomotive brakes, you are typically limited to only 2 or 3 graduated releases per application).
A minor point that could be added to this section would be a mention of the D-22L brake system, which was the original HSC locomotive brake schedule. D-22L used the service and emergency valve portions of the D-22 passenger car brake schedule, with additional portions (including a unique brake stand and independent brake valve, visually resembling, but not interchangeable with, 24RL equipment) to allow for independent brake and other locomotive braking functions. To my knowledge, only 1 operable locomotive still exists with D-22L, CB&Q EMD E5A 9911A, at the Illinois Railway Museum. Wuhwuzdat ( talk) 17:18, 16 May 2009 (UTC)
Please discuss any rationale for changing to another Dialect here. Wuh Wuz Dat 22:10, 23 November 2010 (UTC)
An annotated cross-section of a modern (but straight air) triple valve would be helpful. Even better would be an animated diagram! Casey ( talk) 02:21, 5 July 2011 (UTC)
It would seem that air brakes for trucks and trains are based on the same principles, have similar advantages, similar history (they spread to trucks after Westinghouse proved them in trains) and have somewhat similar circuits (barring such additions as antilock systems on trucks) so we could save a good deal of duplication by merging them into a common article. Thoughts? -- Chetvorno TALK 21:42, 9 August 2012 (UTC)
There's a lack of contents on this article: mainly the problem is that only the Westinghouse brake system used in the US is explained. Here in Europe Knorr Bremse was the pioneer of brake equipment and already in the early 50s was developing a new generation of Control Valves different from the "Triple Valve" to reach the inexhaustible condition.
Already in 1959 the "KE.1a" brake control unit was able to apply gradual brake release by proportional control of the brake to the cylinders and also preventing the auxiliary reservoir to run empty by using a secondary equalizing reservoir used as "pressure imprint": in this way only if the auxiliary reservoir is back to the nominal pressure the brakes could be completly released.
Of course in modern times european passenger coaches used the main reservoir pipe to supply air to the auxiliary reservoir from the locomotives allowing faster filling time and brake release related also to the use of "R" brake capability with the support of electric survelliance preventing skid it high speed.
Not to be forget that in UK in the early years the Hardy vacuum brake was in use and it is still a standard in many English-made narrow gauge systems as also by the Austrian 760mm rail system.
Also to be noticed, Swiss railways was equipped with Oerlikon brake system, should be the first company to develope the Self regulating brake control valve; I don't know if also French railways had a different type of brake.
Minor brake system could be recognized within Europe, such as Dako, Bozic, former Hildebrand Knorr and Kunze Knorr, Breda (only in Italy as a result of protectionism), Westinghouse Hannover and Westinghouse Torino. Fur sure Russia had it's own brake type certainly developing same results as American and European developers. — Preceding unsigned comment added by Hosdo ( talk • contribs) 15:44, 16 October 2012 (UTC)
Beg to disagree, somewhat. Continental European air braking originated with an American expatriate, Jesse Carpenter, who lived in Russia and developed an air brake arrangement for the Prussian State Railways. This occurred after the 'invention' by George Westinghouse so Carpenter would have been aware of the technology. Carpenter had recruited a young technician from the Prussian State Railways whose name was Georg Knorr. Knorr later became the owner of Carpenter's company and renamed it Knorr Brake (Bremse, in German). The K-B company went on to develop the quintessentially European equipments (the previous contributor has named some of them)... but the original concept should be acknowledged as having post-dated the work Westinghouse (and certain others) had already done. The 'graduated release' functionality of European equipment was always possible because European freight trains were short where American freight trains were getting longer all the time. The inapplicability of the Westinghouse triple valve to graduated release (the European practice) was always acknowledged by Westinghouse. So really, all air braking derives in some way from the Westinghouse developments 203.153.205.105 (talk) 10:53, 12 August 2013 (UTC) — Preceding unsigned comment added by 203.153.203.243 ( talk)
Was the Lac-Mégantic runaway train disaster related to the inability of the Westinghouse system to recharge when there is no pressure from the locomotive? The locomotive was shut off due to fire, and hours later the train rolled downhill. 108.160.30.206 ( talk) 02:20, 9 July 2013 (UTC)
I thought I knew how air brakes work but, after discussions at Talk:Lac-Mégantic derailment, I'm beginning to doubt it. I thought the working range of the train pipe was from 0 psi (brakes on) to 70 psi (brakes off). It now seems that the range is 65 psi (brakes on) to 90 psi (?) (brakes off). Is this correct? If so, it would allow some re-charging of the train reservoirs even when brakes are on. Biscuittin ( talk) 02:33, 13 July 2013 (UTC)
One does not need to go all the way to 65 psi to get an application, the further you reduce the brake pipe the more force generated on the brakes, just like your car brakes can be on a little or a lot. Westinghouse only guaranteed an emergency application if there was a minimum of 38(have to confirm this figure since it's late and I'm doing this from memory and I'm tired) psi in the train line. I will try to dig out some reference material and update this article when I can. 0 to 70 psi may be in Europe but I am unfamiliar with this. Besides it's my understanding that most valves in Europe are not by Westinghouse and this article is pretty much only about that valve so operation may be different. -- Daffydavid ( talk) 03:17, 13 July 2013 (UTC)
The following is for "conventional" North American Freight Air Brakes, not EP. Brakepipe pressure can range from 0 psi - 110 psi. China can be 500 kpa (73 psi) or 600 kpa (87 psi). Typically North American freight is 90 psi (except where it isn't!) The way the system works is ELV (Emergency Limiting Valve) is set to say 90 psi. Your ER pressure (Equalizing Reservoir) is then automatically 90 psi. Your BP (Brakepipe) is uaually a pound less at 89 psi. A MIN reduction (Minimum reduction) is reducing ER to 83 psi. BP will follow to within 1 psi of ER. You should get a BC (Brake Cylinder) application of between 7 psi - 13 psi (depends on the railroad). A Full Service application or Lap is a reduction of ER to about 63 psi, with BP within a pound of ER. BC increases to about 63 psi also. Emergency application is when BP is immediately reduced to 0 psi, with ER following more slowly to 0 psi. BC will increase to 73 - 78 psi. There is up to a 1 minute wait before you can recover the Emergency. 15 yrs testing this stuff! — Preceding unsigned comment added by LocomotiveTechEditor ( talk • contribs) 14:21, 3 October 2014 (UTC)
Train Disaster Movies often pretend that braking systems "need to be pressurized", when the modern common standards would in fact brake the train when pressure is released (the reverse of the common plots!). There should be a minor heading regarding this. — Preceding unsigned comment added by 220.245.43.24 ( talk) 04:09, 9 September 2015 (UTC)
The comment(s) below were originally left at Talk:Railway air brake/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Severely underreferenced and those that are listed are not formatted for verifiability. Slambo (Speak) 13:47, 24 October 2006 (UTC) |
Substituted at 01:11, 12 June 2016 (UTC)
There are many types of brake used for service braking, such as regenerative brakes and eddy current brakes, so this redirect is incorrect. A new page should be created for service brake. Should the redirect be immediately removed? Botatao ( talk) 15:14, 30 August 2017 (UTC)
Wouldn't this system be made truly fail safe ... by the addition of a simple spring? So a little pressure has to be retained in the cylinder to keep the brakes released, and if that's vented, the spring pushes the cylinder into the operating position? Anything that requires a positive action in order to work (as this system appears to) is not fully fail-safe and can still be knocked out by anything that prevents that positive action happening. What you need is a passive backstop, such as the aforementioned spring which needs at least some minor positive pressure to defeat and keep the brakes off...? Surely such a modification must have been made sometime in the last 100+ years?? 80.189.129.200 ( talk) 17:11, 19 March 2018 (UTC)
To whit: the "push linkage" between each wheel brake lever looks like it should be higher up on the 14" levers, and particularly *above* some (missing) fixed pivot point on the frame, otherwise when the brake is applied on one wheel, it will be pulled away from the other (and the linkage will not operate in the "push" mode). Similarly, the longer "pull linkage" that connects to the lever directly connected to the cylinder should do so lower down, and *below* a (similarly missing) pivot, in order to actually act as a pull not a push, and so properly activate the brakes on its end of the carriage or truck. The picture is probably 10+ years old now (given edit dates and the software used), and was apparently copied from something drawn up in 1969... it's probably overdue a bit of retrospective proof reading. 80.189.129.200 ( talk) 17:19, 19 March 2018 (UTC)
From the first paragraph in "Limitations" - and that the car reservoir pressure will rise only to the point of thermodynamic equilibrium
What does this mean in everyday-speak? Thanks. Pieter1963 ( talk) 21:03, 31 January 2021 (UTC)
Why do some axles have a disc brake one side and a tread break on the other? eg Toronto GO/Metrolinx cars. Thanks Pieter1963 ( talk) 21:16, 31 January 2021 (UTC)
"Pressure changes during a service reduction propagate at the local speed of sound, ...". Please correct this. I am not certain how to describe pressure changes in a pipe initially charged with compressed air, and later opened at one end, but I am confident that it depends on the rate of escape of gas; propagation of incremental pressure changes will only approach the speed of sound when the rate of escape is zero. Andrewg4oep ( talk)
I've changed a couple references by changing "www.sdrm.org" to "www.sdrm.info", as the latter appears to have a copy of the old sdrm.org/psrm.org website. Is this acceptable, should other parameters in these citations be adjusted, or should these just point to the copy at the wayback machine (if there is one) instead? (At least Diesel locomotive appears to have a reference at sdrm.org in the same situation, BTW: [1]/ [2] (although in that case there is an archive URL there already). njsg ( talk) 10:11, 12 February 2023 (UTC)
The local speed of sound is not the limiting factor in compressed-air systems. That applies only to incompressible fluids. In a train's compressed-air brake system, the limiting factor is the ability of enough air to overcome pipe friction (usually only a 1-eench pipe, plus at least two 45° and one 90° (the gladhand) elbows for each car) and the limiting flow coefficient (Cv) of the exhaust port.
Is "several seconds" correct? It seems like it must take a LOT more time for air to escape through a mile of one-eench pipe and 300 pipe elbows. Drcampbell ( talk) 21:18, 11 March 2023 (UTC)
![]() | A fact from this article was featured on Wikipedia's Main Page in the On this day section on March 5, 2005, March 5, 2006, March 5, 2007, March 5, 2008, and March 5, 2009. |
![]() | This article is written in American English, which has its own spelling conventions (color, defense, traveled) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus. |
![]() | This article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||
|
Here are some other random facts and/or edits I was planning on working in, but I ran out of steam (no pun intended).
I know I'm barely making sense here, but I figured I'd spew all this info out before I forget it all. If anyone can take the above info and run with it, feel free--otherwise I will hopefully not forget to come back and try to straighten this all out. Check out this link, which is linked to at the bottom of the article, and see if you can pry any ideas from there (without performing a copyvio, of course). A quick glance at that page seems to indicate that it's well-written. Also see the companion page discussing specifically North American brake systems.
cluth 05:26, 8 September 2006 (UTC), (who really shouldn't be typing right now)
Not to be overly pedantic about it, but "trainline" is a single word—not "train line." However, what is being referred to in the article as a "train line" is in reality the "brake pipe," which is two words. :-) Generally speaking (in North America) the term "trainline" usually refers to electrical interconnections. I've heard the usage "trainline air" to refer to locomotive main reservoir pressure being conveyed to cars (e.g., for dual pipe brake systems, pneumatic door operators, etc.), but never for the brake pipe itself. We should try to keep the terminology in line with customary railroad practice.
BDD 19:23, 7 March 2007 (UTC)
Just to add some words, I have here a brake supply drawing from a Erie built GE 85 Ton shunter: the air line are named as "Brake Pipe", "Main Pipe" and "Main Reservoir Pipe". -- Hosdo ( talk) 15:51, 16 October 2012 (UTC)
In the UK, "train line" is commonly understood to mean a railway route (e.g. between two cities: "the train line from London to Bristol"). If "break pipe" is an equally suitable terms to train line then perhaps it should be used instead (I'm not a specialist in this area).
Again in the UK, the "trainline" is often the name of the electrical feed used in locomotive multiple working. It means that a driver's desk has been switched on and results in power being applied to the electrical machines - exhausters, compressors etc.
Again, I'm not a train engineer but I do travel regularly by train in the UK. I've never been aware of an engineer connecting pneumatic pipes between trains as two trains are combined into one (or vice versa). Do UK trains use a pneumatic line, or do they tend to have electronically controlled brakes? This article is written to imply that all train brakes are pneumatically controlled (which may well be the case). Thelem 02:52, 10 March 2007 (UTC)
Here in the USA, we occasionally use the word "line" to refer to a railroad, although seldom with the word train. In North America, any railroader, upon hearing the word "trainline," will immediately think about electrical interconnections that run the length of the train. The same term has the same meaning in electrically propelled subway or elevated trains as used in urban transit systems.
Cables that link the trainlines of one car to another (or one locomotive to another) are often called "jumpers," such as the 27-pin MU cables that join locomotive control systems together. Similar jumpers are used to convey hotel (head end) electrical power back to passenger cars, link automatic door control systems together, and so forth. In other words, most railroaders, at least here in the "New World," will immediately think electrical when trainline is mentioned.
I can't recall ever having heard the brake pipe being called anything but a brake pipe, as it has a very specific role in the overall control of the train. If another pipe passes locomotive main reservoir air pressure back to the cars it is called "trainline air" and is understood to be air at relatively constant pressure (the brake pipe pressure, of course, varies according to how the engineer manipulates the automatic brake). By the way, air connections between locomotives are generally called MU hoses—their function relates to locomotive control and not general train control.
Regarding what type of braking system may be used, it depends on your definition of "train." If you include subway or elevated trains used in metropolitan rapid transit systems (what we Yanks often refer to as the "el" or "L"—the former a New York City term, the latter a Chicago term) into the "train" definition, then no, not all trains use pneumatic braking. For example, the L trains in Chicago use a combination of dynamic (rheostatic) and electromechanical braking and, in fact, the dynamic system is the primary means of reducing speed. There's also an auxiliary track brake that may be used in an emergency if the rails are slippery.
As a practical matter, pneumatic braking styled after Westinghouse's invention is nearly universal on locomotive-hauled trains due to the weight involved and the relative simplicity of the system—especially important if there are a lot of cars. I'm not familiar with the technical details of how UK electric trains are braked, but I suspect that, again due to weight, as well as speed, it is most likely an electro-pneumatic system.
As for coupling up air hoses, the trains on which you normally travel are designed so that all interconnections are built into the coupling mechanism, obviating the need for anyone to get down between cars and connect hoses. This arrangement is very common with electrically powered transit vehicles and is nearly universal on North American rapid transit and light rail (tram or street car) applications.
BDD 05:35, 16 March 2007 (UTC)
Within the global railway industry, the term 'trainline' (one word) is internationally accepted and understood. It refers to a connection (pneumatic or electrical) that is carried between vehicles in a train. It does not refer to a 'rail line' (a line of railway) as has been suggested here. The use of the word 'train' where the writer actually means 'rail' or 'railway' is like a father telling a young child "Look at the big train" when they are pointing to a locomotive. It's OK for the kids but it's Thomas The Tank Engine stuff... it's naff and it has no place in in this section of Wikipedia. 203.153.205.105 ( talk) 10:38, 12 August 2013 (UTC)
Something on the history/development of railway brakes would be of interest... TREKphiler hit me ♠ 18:43, 4 August 2008 (UTC)
This is a bit out of date:
Electro-pneumatic brakes are currently in testing in North America and South Africa in captive service ore and coal trains.
Should be Electronically controlled pneumatic brakes, which by 2012 are going into service. Tabletop ( talk) 22:56, 9 August 2012 (UTC)
See Longest trains
Tabletop ( talk) 11:16, 1 November 2008 (UTC)
I noticed the recent addition of the Westinghouse HSC electro-pneumatic braking system to the article, but the edits missed a few key advantages of this system. Due to the fact that the "straight-air pipe" is charged and discharged by solenoid valves on each and every car of a train with HSC braking (air supplied by aux reservoirs on the cars, charged from the trainline) , it can react much quicker than the standard airbrake system (charged and discharged only at the controlling locomotive, and slightly delayed by the valving). The EP system also allows a much more graduated release than is available via the trainline (with 24RL or D-22L locomotive brakes, you are typically limited to only 2 or 3 graduated releases per application).
A minor point that could be added to this section would be a mention of the D-22L brake system, which was the original HSC locomotive brake schedule. D-22L used the service and emergency valve portions of the D-22 passenger car brake schedule, with additional portions (including a unique brake stand and independent brake valve, visually resembling, but not interchangeable with, 24RL equipment) to allow for independent brake and other locomotive braking functions. To my knowledge, only 1 operable locomotive still exists with D-22L, CB&Q EMD E5A 9911A, at the Illinois Railway Museum. Wuhwuzdat ( talk) 17:18, 16 May 2009 (UTC)
Please discuss any rationale for changing to another Dialect here. Wuh Wuz Dat 22:10, 23 November 2010 (UTC)
An annotated cross-section of a modern (but straight air) triple valve would be helpful. Even better would be an animated diagram! Casey ( talk) 02:21, 5 July 2011 (UTC)
It would seem that air brakes for trucks and trains are based on the same principles, have similar advantages, similar history (they spread to trucks after Westinghouse proved them in trains) and have somewhat similar circuits (barring such additions as antilock systems on trucks) so we could save a good deal of duplication by merging them into a common article. Thoughts? -- Chetvorno TALK 21:42, 9 August 2012 (UTC)
There's a lack of contents on this article: mainly the problem is that only the Westinghouse brake system used in the US is explained. Here in Europe Knorr Bremse was the pioneer of brake equipment and already in the early 50s was developing a new generation of Control Valves different from the "Triple Valve" to reach the inexhaustible condition.
Already in 1959 the "KE.1a" brake control unit was able to apply gradual brake release by proportional control of the brake to the cylinders and also preventing the auxiliary reservoir to run empty by using a secondary equalizing reservoir used as "pressure imprint": in this way only if the auxiliary reservoir is back to the nominal pressure the brakes could be completly released.
Of course in modern times european passenger coaches used the main reservoir pipe to supply air to the auxiliary reservoir from the locomotives allowing faster filling time and brake release related also to the use of "R" brake capability with the support of electric survelliance preventing skid it high speed.
Not to be forget that in UK in the early years the Hardy vacuum brake was in use and it is still a standard in many English-made narrow gauge systems as also by the Austrian 760mm rail system.
Also to be noticed, Swiss railways was equipped with Oerlikon brake system, should be the first company to develope the Self regulating brake control valve; I don't know if also French railways had a different type of brake.
Minor brake system could be recognized within Europe, such as Dako, Bozic, former Hildebrand Knorr and Kunze Knorr, Breda (only in Italy as a result of protectionism), Westinghouse Hannover and Westinghouse Torino. Fur sure Russia had it's own brake type certainly developing same results as American and European developers. — Preceding unsigned comment added by Hosdo ( talk • contribs) 15:44, 16 October 2012 (UTC)
Beg to disagree, somewhat. Continental European air braking originated with an American expatriate, Jesse Carpenter, who lived in Russia and developed an air brake arrangement for the Prussian State Railways. This occurred after the 'invention' by George Westinghouse so Carpenter would have been aware of the technology. Carpenter had recruited a young technician from the Prussian State Railways whose name was Georg Knorr. Knorr later became the owner of Carpenter's company and renamed it Knorr Brake (Bremse, in German). The K-B company went on to develop the quintessentially European equipments (the previous contributor has named some of them)... but the original concept should be acknowledged as having post-dated the work Westinghouse (and certain others) had already done. The 'graduated release' functionality of European equipment was always possible because European freight trains were short where American freight trains were getting longer all the time. The inapplicability of the Westinghouse triple valve to graduated release (the European practice) was always acknowledged by Westinghouse. So really, all air braking derives in some way from the Westinghouse developments 203.153.205.105 (talk) 10:53, 12 August 2013 (UTC) — Preceding unsigned comment added by 203.153.203.243 ( talk)
Was the Lac-Mégantic runaway train disaster related to the inability of the Westinghouse system to recharge when there is no pressure from the locomotive? The locomotive was shut off due to fire, and hours later the train rolled downhill. 108.160.30.206 ( talk) 02:20, 9 July 2013 (UTC)
I thought I knew how air brakes work but, after discussions at Talk:Lac-Mégantic derailment, I'm beginning to doubt it. I thought the working range of the train pipe was from 0 psi (brakes on) to 70 psi (brakes off). It now seems that the range is 65 psi (brakes on) to 90 psi (?) (brakes off). Is this correct? If so, it would allow some re-charging of the train reservoirs even when brakes are on. Biscuittin ( talk) 02:33, 13 July 2013 (UTC)
One does not need to go all the way to 65 psi to get an application, the further you reduce the brake pipe the more force generated on the brakes, just like your car brakes can be on a little or a lot. Westinghouse only guaranteed an emergency application if there was a minimum of 38(have to confirm this figure since it's late and I'm doing this from memory and I'm tired) psi in the train line. I will try to dig out some reference material and update this article when I can. 0 to 70 psi may be in Europe but I am unfamiliar with this. Besides it's my understanding that most valves in Europe are not by Westinghouse and this article is pretty much only about that valve so operation may be different. -- Daffydavid ( talk) 03:17, 13 July 2013 (UTC)
The following is for "conventional" North American Freight Air Brakes, not EP. Brakepipe pressure can range from 0 psi - 110 psi. China can be 500 kpa (73 psi) or 600 kpa (87 psi). Typically North American freight is 90 psi (except where it isn't!) The way the system works is ELV (Emergency Limiting Valve) is set to say 90 psi. Your ER pressure (Equalizing Reservoir) is then automatically 90 psi. Your BP (Brakepipe) is uaually a pound less at 89 psi. A MIN reduction (Minimum reduction) is reducing ER to 83 psi. BP will follow to within 1 psi of ER. You should get a BC (Brake Cylinder) application of between 7 psi - 13 psi (depends on the railroad). A Full Service application or Lap is a reduction of ER to about 63 psi, with BP within a pound of ER. BC increases to about 63 psi also. Emergency application is when BP is immediately reduced to 0 psi, with ER following more slowly to 0 psi. BC will increase to 73 - 78 psi. There is up to a 1 minute wait before you can recover the Emergency. 15 yrs testing this stuff! — Preceding unsigned comment added by LocomotiveTechEditor ( talk • contribs) 14:21, 3 October 2014 (UTC)
Train Disaster Movies often pretend that braking systems "need to be pressurized", when the modern common standards would in fact brake the train when pressure is released (the reverse of the common plots!). There should be a minor heading regarding this. — Preceding unsigned comment added by 220.245.43.24 ( talk) 04:09, 9 September 2015 (UTC)
The comment(s) below were originally left at Talk:Railway air brake/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Severely underreferenced and those that are listed are not formatted for verifiability. Slambo (Speak) 13:47, 24 October 2006 (UTC) |
Substituted at 01:11, 12 June 2016 (UTC)
There are many types of brake used for service braking, such as regenerative brakes and eddy current brakes, so this redirect is incorrect. A new page should be created for service brake. Should the redirect be immediately removed? Botatao ( talk) 15:14, 30 August 2017 (UTC)
Wouldn't this system be made truly fail safe ... by the addition of a simple spring? So a little pressure has to be retained in the cylinder to keep the brakes released, and if that's vented, the spring pushes the cylinder into the operating position? Anything that requires a positive action in order to work (as this system appears to) is not fully fail-safe and can still be knocked out by anything that prevents that positive action happening. What you need is a passive backstop, such as the aforementioned spring which needs at least some minor positive pressure to defeat and keep the brakes off...? Surely such a modification must have been made sometime in the last 100+ years?? 80.189.129.200 ( talk) 17:11, 19 March 2018 (UTC)
To whit: the "push linkage" between each wheel brake lever looks like it should be higher up on the 14" levers, and particularly *above* some (missing) fixed pivot point on the frame, otherwise when the brake is applied on one wheel, it will be pulled away from the other (and the linkage will not operate in the "push" mode). Similarly, the longer "pull linkage" that connects to the lever directly connected to the cylinder should do so lower down, and *below* a (similarly missing) pivot, in order to actually act as a pull not a push, and so properly activate the brakes on its end of the carriage or truck. The picture is probably 10+ years old now (given edit dates and the software used), and was apparently copied from something drawn up in 1969... it's probably overdue a bit of retrospective proof reading. 80.189.129.200 ( talk) 17:19, 19 March 2018 (UTC)
From the first paragraph in "Limitations" - and that the car reservoir pressure will rise only to the point of thermodynamic equilibrium
What does this mean in everyday-speak? Thanks. Pieter1963 ( talk) 21:03, 31 January 2021 (UTC)
Why do some axles have a disc brake one side and a tread break on the other? eg Toronto GO/Metrolinx cars. Thanks Pieter1963 ( talk) 21:16, 31 January 2021 (UTC)
"Pressure changes during a service reduction propagate at the local speed of sound, ...". Please correct this. I am not certain how to describe pressure changes in a pipe initially charged with compressed air, and later opened at one end, but I am confident that it depends on the rate of escape of gas; propagation of incremental pressure changes will only approach the speed of sound when the rate of escape is zero. Andrewg4oep ( talk)
I've changed a couple references by changing "www.sdrm.org" to "www.sdrm.info", as the latter appears to have a copy of the old sdrm.org/psrm.org website. Is this acceptable, should other parameters in these citations be adjusted, or should these just point to the copy at the wayback machine (if there is one) instead? (At least Diesel locomotive appears to have a reference at sdrm.org in the same situation, BTW: [1]/ [2] (although in that case there is an archive URL there already). njsg ( talk) 10:11, 12 February 2023 (UTC)
The local speed of sound is not the limiting factor in compressed-air systems. That applies only to incompressible fluids. In a train's compressed-air brake system, the limiting factor is the ability of enough air to overcome pipe friction (usually only a 1-eench pipe, plus at least two 45° and one 90° (the gladhand) elbows for each car) and the limiting flow coefficient (Cv) of the exhaust port.
Is "several seconds" correct? It seems like it must take a LOT more time for air to escape through a mile of one-eench pipe and 300 pipe elbows. Drcampbell ( talk) 21:18, 11 March 2023 (UTC)