Talk:Valve gear

message: I've put the various valve gears in their own category. Please add future pages (e.g. for Young etc.) in :category:Locomotive valve gear and do not add them to :category:Locomotive parts. Mangoe 03:35, 23 June 2006 (UTC)
thread_title:  Categories 

message: I could use a little help:
#I only know about American (and a smidgin of British) usage. Someone with continental/other knowledge needs to take a stab at expanding/filling in those.
#I also don't know much about the poppet systems. I've looked at Caprotti valve gear, and it could use some help. Someone especially needs to tackle Franklin because it is important to the PRR T1.
#I'm not sure I'm naming the parts correctly. I especially need someone who can name the parts of Baker valve gear.
#I know the idea behind Young valve gear but am not up to actually writing the article.
#Southern valve gear needs a history review.
#Surviving engines with some of the odder varieties would be nice. (I have examples for Baker and Southern.)
#Steam locomotive nomenclature doesn't show much of the valve gear. We may want to help this out more than I've attempted to do, but I'm not sure how.
Mangoe 03:20, 24 June 2006 (UTC)
thread_title:  Improving valve gear articles 

message: Hi Mangoe
Thanks for amending the bit I added about sleeve valves and the Leader. I knew it didn't read well when I wrote it.--7severn7 19:01, 3 October 2006 (UTC)
thread_title:  Sleeve Valves 

message: As so often with steam articles, the bias (of knowledge, not POV) is towards railway locomotives. It would be good if an editor with stationary and marine steam knowledge had a look in here.--John of Paris (talk) 12:42, 17 February 2008 (UTC)
replies: text: I've added a short paragraph on Corliss valve gear with a link to Corliss steam engine#Corliss valve gear.  --Roly (talk) 15:20, 22 March 2013 (UTC)
thread_title: Bias towards railway locomotives

message: I wasn't sure where to add the above link, so I've put it pro tem under the "see also" section. Please feel free to move it to a more appropriate place in the article. --Bermicourt (talk) 20:03, 29 January 2012 (UTC)
thread_title:  [[Trofimoff valve]] 

message: Do we really need two very similar photos of the Walschaerts valve gear at the top of the article? One of these could be replaced by a decent photo of Stephenson's gear. I know Stephenson's is typically inside the frames of a loco but there is at least one exception (a Black 5? named after RS himself) and there were (still are?) some stationaries with accessible Stephenson's gear. Some more photos of less common gears would not be out of place either. Unfortunately, I don't have any suitable photos myself. --Roly (talk) 12:44, 4 April 2013 (UTC)
replies: text: That was . The previous photo claimed to be "a close up on the left-hand Walschaerts valve gear", but omitted the return crank and the return crank rod, both being important components; and it also seemed to give undue prominence to items which are nothing to do with the valve gear - buffers, front axle, chimney and ejector. I wanted to replace that with a photo which showed a complete set of the gear on a British loco. --Redrose64 (talk) 18:33, 4 April 2013 (UTC)
replies: text:  From fairly extensive past searches, there are no useful Commons photos of British locos with Stephenson gear. The Black 5 with the external gear doesn't have a great photo and although I did take some fairly decent ones when I found a saddle tank with a skinny boiler, those of internal gear can't show a decent side view of the overall gear, both link and eccentric. However for German and Austrian locos, where external Stephenson gear was much more common, there are plenty of them. Andy Dingley (talk) 19:23, 4 April 2013 (UTC)
replies: text:  Well, the article is not solely about railway locomotive valve gears, so a photo of the valve gear of a marine or traction engine would be appropriate, and would help to present the wider application of valve gears, most commonly Stephenson's. Globbet (talk) 22:28, 5 April 2013 (UTC)
replies: text:  I have deleted one of the two almost identical photos. I thought it was pointless having both. I still think we should have a good photo of a Stephensons gear if someone can find one. --Roly (talk) 18:47, 16 May 2014 (UTC)
thread_title:  Photos 

message: There is a glaring hole in the article. It does not explain what valve gear actually does. For sure it talks about inlet and exhaust opening and cut off points. It also explains how the clever linkages switch between forward and reverse mode. But at no time does it relate the valve events to the steam engine cycle.
Everybody who even thinks about contributing to this article (and everyone who reads the Talk page) knows that piston and sleeve valves have to be 90° out of phase with the main driving pistons and that the engine will run forwards or backwards depending on whether the valves are leading or lagging the drive. (Okay the valve gear always lags because if it leads the engine reverses direction.) But this is never explained. Consequently the purpose of the clever linkages remains a mystery to anyone who doesn't already know what they are for.
As an example it is explained that the Stephenson Motion has two eccentrics and you can see how the Stephenson link allows the Radial arm to select which eccentric to use. But it does not specify the phase angle between the eccentrics and the power crank nor does it show what actually happens inside the steam chest.OrewaTel (talk) 12:30, 13 June 2020 (UTC)
thread_title:  What is the point of valve gear? 

message: I've recently created a page on Cornish engine valve gear. I was planning to link to it from this page, however there seems to be a strong concentration on rotating engines and I'm not sure where best to slot it in. Any suggestions ? Kewnut (talk) 15:03, 1 July 2020 (UTC)
thread_title:  Non-Rotative valve gear