Talk:Walschaerts valve gear

Name

The bit about the name doesn't read quite right, in my opinion. This is a valve gear invented by a man named Walschaerts, so if anything could be said to have a proper name, it probably ought to be "Walschaerts valve gear" in this case. It has come to be known much of the time as the "Walschaert valve gear" because someone got his name wrong somewhere in the patenting process. Patents do not create some overriding name that should properly be used over what common sense tells us something should be called. US patent 3,156,523 is titled "Element 95 and Method of Producing Said Element", but the IUPAC standard name of this element, which is the closest thing to an 'official' or 'proper' name, is Americium. There must be countless examples of patent titles which do not reflect either common or standardised 'proper' usage. There's no problem having this article at "Walschaert valve gear" if that's how it's more commonly known, but it's no good to say that's how it's properly known, when really it's just an error that has become widespread. 81.155.83.249 12:27, 1 September 2006 (UTC)

I think it's just a mistake that's been carried on over the years. Probably to do with the apostrophe. People have taken Walschearts valve gear to mean Walschaert's i.e. invented by Mr Walschaert, whereas his name is spelt 'Walschaerts' So I suppose it could even be 'Walschaerts's Valve Gear' :-) ChrisRed 160.84.253.241 15:59, 12 January 2007 (UTC)

Second thoughts...I'll have a go at simplifying this soon. It is flagged-up as 'too technical' and is also actually wrong in a couple of places (i.e. return crank/combination lever layouts for slide/piston valves) and it doesn't say what 'lap' and 'lead' are. I'll put my version on this 'Talk' page first for comments. ChrisRed 13:40, 24 January 2007 (UTC)

It's the least courtesy to spell the man's name right, for crying out loud! Even if he is long dead, the name is fairly common in Belgium. I'm for renaming the article Walschaerts valve gear and putting Walschaert in brackets. As for lap and lead, I've just tried to give a simple explanation in the Steam engine article, section: Steam distribution. I'd be interested in your reactions. The point is, you can't explain lap and lead without first giving an idea of the whole steam engine cycle.--John of Paris 11:25, 8 June 2007 (UTC)

Anybody there?! It's been three weeks since my last contribution to this discussion. As I said, I'm for renaming the article. Personally I have never seen the name "Walschaert" in any English language publication, so I don't think we can consider it common usage. I'll wait another week then change the title. Considering its high importance rating in the trains wiki, the job should not be shirked and the other problems should be addressed pretty soon.--John of Paris 08:46, 29 June 2007 (UTC)

I've mentioned this discussion on the project talk page. Personally, I have no strong feelings toward either name. Slambo (Speak) 11:13, 29 June 2007 (UTC)

Thanks Slambo, for directing me to this. FWIW, I think it should be moved, firstly to get the mans name right, and secondly beacause that is how it is referred to in general use. regards, Lynbarn 11:20, 29 June 2007 (UTC)

Look, anyone would think I'm bringing up a new issue. This is the only subject on the present discussion page and if you look back through the history of this article over the past year, you will see that there have been at least two attempts to move it. It hasn't been moved or been moved back each time which suggests to me that someone is hanging on by his fingernails. Well I don't like charging in like a bull in a china shop into an article in which I have never participated and just doing a fait accompli. All you are discussing since last September is one letter S. — What comes out of the discussion is that nothing justifies keeping the present title - but I as a newcomer would rather those who contributed took the initiative... That said I will very happy to participate in resolving the other problems and see us discussing here something interesting - but please, first move it.--John of Paris 20:16, 29 June 2007 (UTC)

The article has been moved to its new name, and I have amended the copy to reflect that, but there are still some wikilinks that are currently redirected, which will need to be repaired. If you can do some, please do, if not I will go through this list and this one too in the next few days or so. regards, Lynbarn 00:40, 30 June 2007 (UTC)

Phew! Thanks Lynbarn!--John of Paris 13:36, 30 June 2007 (UTC)

Many years after the fact of placing this under the Walschaerts name, I would refer readers and editors to the PRR Technical and Historical Society style manual which says "His name was Walschaerts, but the design was patented under the name Walschaert for political reasons." --Dhlocker (talk)

References

The best article I have ever seen on Walschaerts (what a name to spell!) and his gear is in French by Jacques Payen in Les Cahiers Chapelon a magazine supplement that came out in the 1980s. In it he gives an account of the dispute between Heusinger von Waldegg and Walschaerts in which both parties come off honourably. Walschaerts position, which he held all his life was works manager on the Belgian State Railways. I have drawn from it to update the Egide Walschaerts article.--John of Paris 17:36, 30 June 2007 (UTC)

Too technical

This is a good article: the animated images are excellent, and the explanation of the technical details seems very thorough. However - it's just too technical for a general reader to follow, or a kid doing homework, I'm afraid. The technical section is fine if you are already a mechanic or engineer, and familiar with that kind of thing; if not, it's pretty much Greek.

I wouldn't suggest changing anything there, but I would, per WP:TECHNICAL, like to see a brief overview or summary section written in layman's terms. This would explain that steam from the boilers is fed into the valve chamber, which pushes the rods/linkages, which turns the drivers, which via the linkages again makes the valve move, and thus you get a locomotive rolling down the track.

Moreover, what starts, what stops this process? I happen know that the engineer pulls the throttle, which opens a valve in the steam dome, which lets live steam move down a pipe into the valve chamber, and by closing the throttle, the engineer can slow or stop the whole process. But that's not in this article, nor is it very clearly explained even at steam engine.

Because I've seen videos before that explained the whole working of a steam locomotive, I have a rough idea of the process, as stated, but I'd rather someone more familiar with the technical terms than me write the layman's explanation. I'm open to collaboration on that, if anyone wants to do it. Textorus (talk) 14:22, 22 September 2010 (UTC)

The reversing lever plays a very important part in the process; a widely accepted practice was to open the throttle (regulator) fully and then use the reversing lever to restrict the movement of the valve- this in turn cut off the supply of steam to the cylinder part way through the piston's travel. The union link and combination lever provide 10% of the movement of the valve- this 10% is invariable, the other 90% is produced by the eccentric rod and radius bar (I'm writing this off the top of my head so please excuse any inaccuracies). So if the gear is put in "neutral" and the loco moved the valves will still go back and forth, but only by 10% of their total possible travel. Can't remember the reason for this, but I vaguely remember that it is supposed to be of fundamental importance. Willing to help out, but I've not got much technical knowledge. Ning-ning (talk) 19:58, 22 September 2010 (UTC)

I think it's impossible to have an article on Walschaerts valve gear that doesn't rely absolutely on a serious level of technical understanding of steam engine valvegear.

The best we can hope for is to redirect readers who don't have such an understanding to a "primer" article beforehand. IMHO, the best structure for such an article (and a good topic in its own right) would be on the historical development of valvegears. This is not only a useful history, it's also the most approachable manner in which to read of their increasing complexity over time. A rough structure would be as follows:

• Plug cocks in beam engine
• Gab valvegear
• Opposed gab valvegear, and the development of the single reversing lever
• Link valvegears, such as Stephenson-Howe
• Radial valvegears, Joy
• Walschaerts
• Cam and poppet gears, Caprotti etc.
• Trip valvegears (big stationary mill engines)
• Corliss, both Corliss semi-rotary valves and Corliss valvegear

Andy Dingley (talk) 20:14, 22 September 2010 (UTC)

Well both of you may have good ideas for people who are technically competent before they get here, but I think you're also missing the point of my comment above. A kid - or in the 21st century, his dad or mom - who has never seen a steam locomotive in person, just in the movies, comes to WP wanting to know how it works, what makes it move? So far, I've not found an article that explains the process in everyday language that a 7th grader or a non-mechanical adult would easily understand, which is the point of WP:TECHNICAL. If the Walschaerts article is not the best place for that kind of simplified explanation, where can we redirect such readers to find one? Textorus (talk) 00:59, 23 September 2010 (UTC)

The engine boils water to make steam. Steam is water in gas form. A little water makes a lot of steam; because the engine boils the water in a confined space the steam is at a high pressure, more than 5 times the pressure of the air in a car tire. The steam goes through pipes to valves which are connected to cylinders. The valves let the steam into the cylinders either into the front or the back of the cylinders. In the cylinders are pistons which are pushed backwards and forwards by the steam; when steam comes in at the front of the cylinder the piston is pushed back and the steam that was at the back of the cylinder is pushed out and up the chimney. When the piston gets all the way over to the back, steam is let into the back of the cylinder and the piston is pushed forward. The pistons are connected to the wheels, and the back-and-forward motion of the piston turns the wheels by a crank, just like the crank on a bicycle. The engine starts because it has two or more cylinders; in at least one of the cylinders its piston is in the right position so that if the steam presses on one side of the cylinder it will start moving in the right direction. The reversing lever allows the driver to change the position of the valves so that the driver can choose which side of the piston the steam goes in, but only when the engine is stopped. This allows the engine to go backwards when the driver is reversing into a parking space.

Walschaerts was a famous Belgian. He is not one of the six famous Belgians, but another one. He designed how to connect the wheels and the cylinders and the valves together in a way that works, but that no-one now living understands.Ning-ning (talk) 06:48, 23 September 2010 (UTC)

• If you don't know how a steam locomotive works, steam engine would be a better starting point. Walschaerts_valve_gear just isn't the right place to start, and I doubt if this hypothetical schoolkid would be starting to look from there anyway.

As a general problem with WP though, broad articles at that level are always poor and usually unreadable as a coherent work (odd paragraphs might be good, but there's no editorial control of the whole article). Steam boiler is pretty poor too, for much the same reason. Andy Dingley (talk) 14:25, 23 September 2010 (UTC)

--EdinburghEngineer (talk) 22:56, 23 July 2012 (UTC)

I have had a go at simplfying some of the article hopefully to make it more accessible to the reader and have removed the too technical tag. I do hope this meets with approval. What would be great if User:Duncharris could develop an animated gif of the valve gear starting from rest (forward) and then the valve gear being adjusted to a more economical central position. This should show the amplitude of motion of the piston valve being much reduced and therefore less steam being used. Chris

Query

The article has had for many years:

The Walschaerts valve gear is an improvement on the earlier Stephenson valve gear in that it enables the driver to operate the steam engine in a continuous range of settings from maximum economy to maximum power.

but is this true?

86.162.138.249 (talk) 01:57, 17 April 2017 (UTC)

Mhm. Not really. --User:Haraldmmueller 18:35, 14 October 2018 (UTC)

How do you pronounce "Walschaerts"?

See above. — Preceding unsigned comment added by 116.48.250.218 (talk) 06:26, 3 May 2021 (UTC)