Do you want a real technical explanation of the 'poppet value' ? Try this site! http://lmhibm5.epfl.ch/SiLMH/fidap8.5/examples/ex13.htm Saw were the British used poppet values on their 1935 steam engines. US a few years behind. ....Eddie ------------------ Eddie Delozier PRR N-scale www.deloziers.com eddelozier@yahoo.com [This message has been edited by eddelozier (edited 19 January 2001).]
One of the beauties of a popet system was that it could turn higher rpm's with less vibration and was pressure lubricated. The lack of the eccentric mechanism looked cleaner. Setting the popeds, was a bear, but once they were tweeked in, it was said this engine could wind it up quicker and tighter than the standards. The expence of manufacture and tuning up, and maintainence, may have made them seem impractical. Could be. But you got to admit, "There is nothing like a Niagra"! ------------------ Watash #982
Eddie, that description of Poppet valves was too technical for me. I found an advertisement in an old Locomotive Cyclopedia run by Franklin, mentioning both "type A" and "type B" systems. I know I have seen a good set of drawings on such a system, but can't remember where. Watash, thanks for your insight, as always, and yeah, there's nothing like a Niagara. ------------------ http://www.pioneer.net/~fitzrr/ Member No. 508
I got a model and a pic of #s 5016 & 5500 #5500 model has an eccentric rod. INACCURACY (unless 5550 had the "Poppet" added later) ------------------ TrainBoard.com MEMBER#204 THE WEB PAGE IS NOW UPDATED!! Appalachian & Atlantic Model Railroad "QUALITY at WORK with SAFTEY in MIND"
While on the subject of Niagara's.I still need some photos of the smoke stack/whistle area,from the top. I am redetailing a nice old Kemtron,yes Kemtron ,O Scale model.I have some photos but I need some more.Yes I have tried the importers and have had mixed results with them and feel that someone out there has GOOD photos. How do I know that I have a Kemtron you ask? My #8 All Nation catalog has a photo of same and the engine has the same detail problems mine has. You say All Nation?Yes. At one time AN carried products from other sources as well as there own and they also had one of the largest hobby shops in the country in Chigcao. A later Kemtron catalog show a Niagara with more detail.Ummm maybe I have the pilot model...... Ron Morse
Ron, you must be the expert on NYC O gauge modelling. I don't even know about those companies, mainly because I have been out of modelling for some 45 years. WT&C, I assume that was 6016 and 5500. 5500 was purpose-built with poppet valve system so the model photo is inaccurate, as you said. Several railroads experimented with poppet valves, and I'm sure if the diesels hadn't displaced steam, that would be the way the steamers would be built. ------------------ http://www.pioneer.net/~fitzrr/ Member No. 508
let mee look here at my models:.....Hmmmm. #5500 No poppet valves (I have something to do now!! ) #5016 That the way it is, or Bachmann's version well that's another thing to do today, renumbering. !! ------------------ TrainBoard.com MEMBER#204 N.A.R.A. Member #8 THE WEB PAGE IS NOW UPDATED!! Appalachian & Atlantic Model Railroad "QUALITY at WORK with SAFTEY in MIND"
Some errors have crept into these postings-possibly because most of us use the "hunt and peck" method of typing? There was only one poppet valve Niagara-it was road no. 5500. The standard S-1b Niagaras were nos. 6001-6025. There was only one S-1a Niagara-it was No. 6000. The #5500 had type A1 poppet valves, and the valves were actuated by a sealed and oil bath cam box that was located on the front pilot deck (This required moving the air pumps to immediately below a raised running board on the fireman's side of the engine). With the use of poppets, total engine weight increased from the 471,000 lb (engine only-less tender) of the standard Niagaras, to 485,000 lb. The 5500 threw its rods at least two times when in service-once along the station platform at Dunkirk, NY after descending the long and gradual grade westbound out of Buffalo at high speed. (The reason for the thrown rods was that the spun brass collars in the Timken rod assemblies were worn as a result of running with no clearance steam in the cylinders at each end of the piston travel to "cushion" the piston before it reversed its direction. The "drift" setting of the poppets caused this problem and it was disabled and the engine ran fine. The engine had "only" 5000 drawbar HP and could not equal the performance of the standard piston valve Niagaras when tested, although it had 15% lower fuel and water consumption. A review of the cylinder bed casting showed that 5500 inlet port would only flow 100,000 lb. of steam per hour, as opposed to the 135,000 lb./hour capability of the standard piston valve engines.
Tom, thanks for correcting us. I know I get sloppy typing. Added a non-existant serial no. (6026) to the list. Now, I am very interested in the fact that 5500 weighed more. Did the poppet valve system weigh that much that it offset the removal of the eccentric rods and Baker gear hangers? The 5500 had air pumps on both the engineer's and fireman's sides.
Fitz, I do not know what the actual weight difference of the poppet valve system was, just that the total engine weight went from 471k to 485k. Obviously, there was the difference in the engine bed casting in the cylinder area and this may have been a weight increase or a decrease....I seem to remember reading in Vern Smith's book "One Man's Locomotives" that the cam gear box on the PRR 4-4-4-4's weighed about 3800 lb. so this may give some idea of a major weight item (although I am not sure that the box was the same on the #5500). The advantage to the poppets was that the weight did not move, by revolving as Baker valve gear did, so the engine was probably easier to balance and better on the track. (It is true that the valves themselves moved like the valves in an automobile ie they reciprocated. However, they were much lighter in weight than the spool valve of the Baker valve gear.)
