# Stack talk



## iceclimber (Aug 8, 2010)

Ok, so watching numerous videos and seeing live steamers run up close, I have a question concerning stack exhaust. I notice on some engines that there is a lot of steam coming from the stack while others show more steam coming from the safety valves while running. What makes the difference? I understand about weather and steam, but speaking purely of the locos, why do some show steam from the safety valves and little to none from the exhaust stack?


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## artgibson (Jan 2, 2008)

Jeremiah
I dont know the reason for it but I do know that my Arglye 4-4-0, My Accucraft Shay and my Roundhouse SRRL"s have way more Plumes than any of my other engines including my Aster engines.
The safety valve situation is purly a matter of the boiler letting out excess steam, the exhaust from the Stack is I presume a comination of extracing oil residue and moisture from the pistons. My guess though.


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## Pete Thornton (Jan 2, 2008)

Posted By iceclimber on 30 Mar 2011 09:08 AM 
Ok, so watching numerous videos and seeing live steamers run up close, I have a question concerning stack exhaust. I notice on some engines that there is a lot of steam coming from the stack while others show more steam coming from the safety valves while running. What makes the difference? I understand about weather and steam, but speaking purely of the locos, why do some show steam from the safety valves and little to none from the exhaust stack? 

Gee, Jeremiah, you ask the darnest questions...

Once you've attended a bunch of "steam-ups" and asked a few questions you'll see the answer, but let me try to put it in words.

Steam comes from the safety valves when the pressure is sufficient to make them open. My personal observation is that Aster locomotives tend to popping the safeties - and they use a different type of boiler and different safety valves from Accucraft locomotives. Accucraft locos, on the other hand, tend to make steam but not pop the safety valves until the boiler is really hot, and they tend (again, personal observation) to have more of a steam plume.

Steam from the stack depends entirely on how much work the loco is doing and what atmospheric conditions are like. In Florida you won't see much steam any time except first thing in the morning before the sun warms everything up. In a northern winter you get lots of nice steam effects, but who want to run trains in freezing air?


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## iceclimber (Aug 8, 2010)

Thanks. I was wondering about that. I guess the exhaust steam is used up and therefore isn't as plentiful as the steam coming out of the safety valves. A quick comparison could be made by watching any videos of say the USRA 0-6-0 by AML vs. the Accucraft/g1mc's britannia. I have never seen a plume come from any videos I have viewed of the Britannia, nor the one I saw in person. So, therefore this was the basis for my question. 

Pete thanks.

Last time I checked this was a public forum and a forum is for discussing things, asking questions and providing help. Without my "darn" questions, what would be the purpose of this board for me? I hang out at home with my family, I don't come here to hang out, but more get info, share and learn from others and get a steam "fix". Sorry, if my questions come off as rather inane to the more experienced. I gather in all things one can learn and teach. If you were to say, ask me a question about glacier travel, I believe I could teach most of you more than you know, but that is neither here nor there. Thanks for the info Pete.


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## Pete Thornton (Jan 2, 2008)

Posted By iceclimber on 30 Mar 2011 10:04 AM 
Thanks. I was wondering about that. I guess the exhaust steam is used up and therefore isn't as plentiful as the steam coming out of the safety valves. A quick comparison could be made by watching any videos of say the USRA 0-6-0 by AML vs. the Accucraft/g1mc's britannia. I have never seen a plume come from any videos I have viewed of the Britannia, nor the one I saw in person. So, therefore this was the basis for my question. 
As I mentioned in the post that crossed with yours, a lot depends on the air conditions. These two videos are the same loco - first is at Scranton in a cool dry museum, and the second was taken on a sunny May day outddoors.


*Scranton Steam-Up Feb 2011 PT C-19 Chuffer* 

*C-19 w/Chuffer* 
_P.S. Sorry if my post sounded testy - you're entitled to ask anything, and I'm entitled not to reply if I'm feeling grouchy. Sorry!_


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## iceclimber (Aug 8, 2010)

I understand about how steam works in relation to the ambient air temperature. Now, I have NEVER seen the britannia produce a plume even while working hard. In the test video of the britannia pulling all those cars, one can see a bit as it chuffs away from a dead start, but while it is running around that track it is not showing an exhaust plume. Now, I am presuming that the video was taken on the same day under the same temps. Also, on a day which I witnessed the britannia run in person, I could see plumes come out of an Acc. Climax, but none what-soever out of the britannia. Just asking why is all. It would seem that perhaps the Britannia must be put to the test at it's fullest to produce a stack then.

Pete, I am used to tenting with the same people for weeks at a time in a climate which brings out the worst in people due to isolation and extreme conditions. I might snort a few times, but in the end, I let the water roll off my back, so no worries. I am used to speaking my mind though, in as respectful a manner as I can muster. 

For your reference. Note the last 2 minutes of the vid.

http://www.youtube.com/watch?v=Ga2uUXRNK74 


Pete, those videos are both different to be sure in terms of size and density of the plume. My point is, that on some it really can't be seen at all and if so, not even as much as that C-19 on a warm day in May. I know I am being a bit picky and anal about the detail, but after all, don't you get a smile on your face from seeing a nice stack of steam as opposed to none? I know I would have a grin from ear to ear.


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## rwjenkins (Jan 2, 2008)

One major difference between the Britannia and the Climax is that the Britannia is alcohol-fired while the Climax is butane. In an alcohol-fired engine the exhaust steam provides draft for the fire, just like on a full-sized locomotive. That means the exhaust nozzle is low down inside the smokebox and the exhaust steam has more direct exposure to the hot flue gases, making it more likely to evaporate before it has a chance to condense into visible water vapor. In a butane-fired engine, the exhaust steam is not used to draft the fire, and the exhaust tube typically extends high into the smokestack before releasing the exhaust steam into the air. The closer the top of the exhaust tube is to the top of the stack, the less exposure the steam will have to the hot flue gases, and the more visible the plume will be. Roundhouse engines, for example, tend to have more visible plumes than Accucraft. Cutting off the crimp on the exhaust tube on an Accucraft engine will also improve the plume, but keep in mind it will also give you a rather spectacular fountain of hot oily water when you're clearing the cylinders!


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## iceclimber (Aug 8, 2010)

Richard, 
thanks so much. Your explanation makes perfect sense and therefore closes the issue with me. I appreciate that. Is there a way on alcohol fired locos to raise the height of the exhaust nozzle, or would that interfere with the draft then?


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## afinegan (Jan 2, 2008)

You usually don't want to mess with the draft nozzles, they are there to grab the surrounding air and coax it up the stack. It is a vital part of an alcohol/coal burning steam engine (any with a draft). Some crazy draft nozzle designs - yes it all applies even when scaled down(even though it will act different than the 1:1 counterparts - some things don't scale down) - http://www.trainweb.org/tusp/ex_dwgs.html 
You can have great plumes in the winter time in the orlando area, here is the first video I took of my fathers K-28 on a cold christmas weekend evening (in the dark, but you can still see the steam from the plume and the Welkty whistle). I wish I could get those plumes down here in South Florida but most of the time I dont.

Video:
http://www.youtube.com/watch?v=n4qY32mlwVY


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## iceclimber (Aug 8, 2010)

Andrew, 
Thanks for the link. upon further investigations, it is indeed rare to see an alcohol fired engine with as nice a smoke plume as a gas fired one can produce. Guess those are the trade-offs between fuel types.


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## afinegan (Jan 2, 2008)

Thats what a coal burner fixes!:




Here is an aster alcohol fired Berkshire putting off a plume show - still not that much (but it was very cold on this day and 100% humidity) - the steam at the bottom of the engine is the drain cocks being open to clear the cylinders of condensate, pretty neat:


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## iceclimber (Aug 8, 2010)

I remember your coal fired ruby put off some plume last month. Yeah, here in Central Florida, don't think it would get cold enough for a good plume like the Berkshire. That looked good with the drain cocks open too.


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## David Leech (Dec 9, 2008)

Jeremiah, 
You will also find that a NON superheated loco will always put out a good plume of steam out of the stack as the exhaust steam is wetter and will not be dried by the flue gasses as much. 
All the best, 
David Leech, Delta, Canada


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## iceclimber (Aug 8, 2010)

David thanks.


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## Charles (Jan 2, 2008)

Posted By afinegan on 30 Mar 2011 01:38 PM 
Thats what a coal burner fixes!:




Here is an aster alcohol fired Berkshire putting off a plume show - still not that much (but it was very cold on this day and 100% humidity) - the steam at the bottom of the engine is the drain cocks being open to clear the cylinders of condensate, pretty neat:

 
Always enjoyed that day and the start up of our Berkshire....
 
On the topic of superheated vs. saturated steam can you tell which Cab Forward is running as to the configuration?
 
The Aster K4 can impress both with "stack talk" as well as plumes:
 

 
After a brief summer shower combined with the moisture in the air: 

 


Forgot the cab forward video for comparison saturated vs superheat setup of two cab forward and cannot edit into post according so here it is:


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## Steve S. (Jan 2, 2008)

Was told a while back that on most butane fired locos there is a opening at the bottom of the smoke box under the steam exhaust pipe. (It's like that on my SR #24 and Catatonk 24 ton Shay) Because of this, cool air is pulled in mixing with the exhaust steam, cooling it, causing it to become more saturated and............. thus creating a better plume. On a alcohol fired engine, all is sealed so a dryer, less saturated steam escapes with less plume. Of course outside temperature and humidity factor in greatly.


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## Dwight Ennis (Jan 2, 2008)

My experience is almost entirely with Accucraft with a couple of Catatonk locos thrown in. That said, the amount of time the safety is blowing off steam is related to how hot one runs the fire. If steam is blowing from the safety all the time, you're making more steam than you are using for the work being done and can probably afford to sneak the fire down a bit. I try to run my locos so that the safety is NOT blowing steam all the time as it conserves consumables and extends run times. 

One other thing I've noticed (I think) from personal experience is that Accucraft locos tend to have better plumes at the beginning of a run when the lubricator is freshly filled. Once the oil in the lubricator starts getting mixed with a fair amount of water, the plume thins out a bit. This isn't something I've tested - rather something I've noticed in passing (which is why I said "I think"). More an observation that an actual fact.


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## iceclimber (Aug 8, 2010)

Dwight, that makes sense with the oil mixed with steam exiting the stack, as the oil winds down, so would the density of the plumes. You mention if the safety is blowing off all the time then too much heat is being generated. How would you adjust this on an alcohol fired loco since you can't regulate the heat as much?


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## livesteam53 (Jan 4, 2008)

Dwight you are right saying "I THINK".. 
I think that also but are not real sure.


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## ChaoticRambo (Nov 20, 2010)

It is important to remember a significant difference in Butane/Alcohol fired engines and coal fired engines (including real ones).

Butane and Alcohol burn "clean" so you are not getting any actual smoke, everything you see coming out of the stack is steam. 

On a coal engine, only really one thing affects the size of the "plume", which is how hard the engine is working - even smoky engines put nearly nothing off when they are going down grade because they are not working hard. However, the steam they put off is still affected by the bellow factors, we just tend to notice the smoke more than the steam.


For our engines though, at least those of us that use Butane and Alcohol, the factors that affect our "plumes" are a little more fine.

#1 is always the outside temperature, the colder it is - the more impressive the plume will be. 

#2 would be the inside temperature of your cylinders and smoke box, have you ever noticed your engine tends to put off a larger plume when you first start running? This is because the cold"er" metal (just like colder air) will make the plume more visible. 

#3 is the pop-off. When the pop-off is going off, not only are you wasting energy (not using all the steam you are producing), but it will significantly reduce the size of your plume. 


All three reasons sill are caused by the same effect. Steam is obviously generated by boiling water, the rate at which that steam returns to its liquid form is directly proportional to how cold of an environment it is in. The "white" steam is the steam is turning back into its liquid form, the "clear" steam is steam that is not quickly turning back into liquid.


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## iceclimber (Aug 8, 2010)

Thanks guys for the explanations, especially yours ChoaticRambo. Everything makes perfect sense. So, on a lot of the meths fired locos I have seen, most have the safety blowing out steam the entire run. Is there really no way around this as you really can't turn down the heat? That is one difference I have also noticed between gas and meth fired locos. The gas fired ones seem to not have the safety going off the entire run. Well, almost all of them anyway.


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## David Leech (Dec 9, 2008)

Posted By iceclimber on 30 Mar 2011 07:44 PM 
Dwight, that makes sense with the oil mixed with steam exiting the stack, as the oil winds down, so would the density of the plumes. You mention if the safety is blowing off all the time then too much heat is being generated. How would you adjust this on an alcohol fired loco since you can't regulate the heat as much? 
Jeremiah,
NOT an easy thing to do!
I tend to put new wicks in so that I know that they are a little too large.
Then after a few runs after I see how the loco performs, I can start cutting the wicks down.
On my Royal Hudson, I discovered that the 'new' wick material does NOT like being messed around, so ended up having to put new wicks in each time.
At first I went just a little low, so that in around freezing temperatures it would never quite blow off and did not have quite enough 'get up and go'.
Now I have it running great in cold weather, but will probably find that in California it will just blow off all the time!
The other thing is that it depends on the weight of the train and the type of track that you are running at.
It all ends up as a compromise!
If the wicks are a little lacking, then you can open the blower just a little to help things, but if you have to do that too much, then of course you might just end up using extra steam as well. 
There is a gentleman in the UK that has built his burners with adjustable height wicks so that as the 'gas' guys do, he can adjust his fire to get it just right.
Maybe Accucraft can perfect it and put it in their locos!
It makes it more interesting than just turning on the gas!!!!!!
David Leech, Delta, Canada


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## ChaoticRambo (Nov 20, 2010)

As I do not have experience running meth fired engines I can not speak about them specifically, however safety valves are the same no matter the fuel.

The general principle is that a boiler is built to run at a pressure x. Safety valves (typically two) are set to a pressure x+ c and the other one is set to pressure x + c + c (higher to increase release when needed). No matter the source for generating a fire, you are using the heat to boil water. This steam is then used to move the cylinders. The further open your reverser, the more steam you are using per stroke (which is why most engines used70-100% reverser at start, and 20-30% at speed). Your throttle will also increase the amount of steam you are using.


If your fire is generating more steam than you are using, the pressure will increase in the boiler until eventually it hits the pressure the safety valve is set to, and the steam is then released until it is back down under the pressure of the safety valve.

In real life, firemen HATED it when the safety valve was going off because that meant that some of the coal they just shoveled is not going to moving the engine, it is being wasted out the safety. This is why engines were run by two people, a firemen, and an engineer - each had their roll in keeping the engine running smoothly and at a good efficiency (as good as they could get).


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## Dwight Ennis (Jan 2, 2008)

How would you adjust this on an alcohol fired loco since you can't regulate the heat as much?Qthers have already answered this, but as you asked me, my response is that I have absolutely no experience with alcohol so I have no answer.


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## Charles (Jan 2, 2008)

At first when I read the topic I thought it would focus on what causes stack talk as in petticoat, blast nozzle, load, grades, beginning able to hear exhaust beats, some even believe you can tell efficiently or lack thereof.


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## iceclimber (Aug 8, 2010)

charles, since I have my answer concerning steam plumes, what does cause certain beats in certain engines. Take the Britannia for example, a nice beat. Could you elaborate just a bit? I know the harder an engine worked, the stronger and crisper the beat.


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## Semper Vaporo (Jan 2, 2008)

You cannot turn the heat up in an alcohol burner. The "chicken feed" type has a sump that fills from the main tank through a valve that can be controlled by the user. When the sump is full the flow is quelled because the air to replace the alcohol in the main tank is cut off when the level in the sump reaches the only opening for air to enter the main tank; a vapor lock occurs and full flow stops. The only thing that empties the sump is the flow of fuel to the burners wicking up the wicks and burning off. When the flow is low enough to expose the air line, air can enter the main tank which lets more fuel flows into the sump, which raises the level to again cause a vapor lock.

However, if you partially close the valve from the main tank to the sump then the flow of fuel can be limited to less than the rate of consumption, which reduces the fire and resultant heat.

In the Aster Mike, there are three burner cups in series on one supply pipe from the sump and if the fuel flow is reduced this usually means the majority of the fuel that does get through is burned in the first cup and a bit less in the middle one and last burner does not get much alcohol, if any.

The instructions for my Mikes said to open the fuel valve about 3 turns, but one of the first times I ran one, I mistakenly counted half turns and thus opened the valve only 1 and a half turns. By the time I got the match lit, enough fuel had flowed to fill all three burner cups and so when I first inspected the fire using a mirror I could see that all three were burning. But it didn't take long for the last cup to be starved for fuel and the fire died down considerably and it took a very long time to get the pressure up. Inspecting the fire again I noted that only the rear cup had fire at all. In an effort to troubleshoot the problem I closed the fuel valve an noted that I had not opened it the correct amount. Opening the valve full then soon provided a full fire and pressure came right up.

Now, when I am running and the draft is really good, the safeties can start blowing off and that is a waste of fuel and water, so I start closing the fuel valve to reduce the fire. It does not take long to get the safeties quieted, but if I close the valve too much it also does not take long to lose power in the engine.

Due to outside influences, ambient temperature, wind, sun on the boiler, etc., there is no "sweet spot" for the fuel valve. In general, I open the valve "ABOUT" 3 turns and once underway, I sometimes close it 1/2 turn and may later make further adjustment... but I only do this if I am intentionally trying to conserve fuel and water and I don't do that very often.

Water consumption is more easily controlled by paying attention to the setting of the Reverser to run in the "Company notch", and strict attention to that can result in significant savings in water. Going from 3 to 4 tender's full of water in an hour to only 2.

Fuel consumption is such a slow reacting process that it is difficult to find a setting that stays constant enough that I am not having to fiddle with it all the time. I have the valve full open (3 turns) and as soon as I have enough steam to move the engine I close the valve about 1/2 turn. If the safeties start blowing off, I close it an additional amount. But to do that requires the engine to at least be slowed so I can get my handful of big-toes in the tender without derailing something, which means there is not as much draft, so the fire dies down which increases the amount of fuel in the burner side of the system, which means that when I open the throttle to start up again there can be a momentary increase in the fire until the change in the flow is evident.

I have not experimented as much with fuel flow as I have with the Reverser to control water usage, so I cannot relate any measured evidence as to the effect on run times when reducing the fuel flow, but I do know that usually I open the valve a full 3 turns and the usual run time is a bit less than 1 hour and when I leave it at about 2 & 1/2 turns it is a bit over 1 hour, but the difference in run times is more affected based on how full I filled the main tank, ambient temps, wind, and how I am handling the train (running fast or slow, starting and stopping a lot), etc. All of which have an effect on run times. It would take multiple carefully controlled runs at full fuel flow and restricted fuel flow to get some averages that are meaningful.


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## Steve S. (Jan 2, 2008)

Yes, alcohol is trickier to adjust the flame then with butane. I used to try and get the alcohol loco's flame adjusted to water being used, keeping the safeties from blowing off as little as possible. It was a real pain in the..............!!!!!! Then one day I realized that seeing and hearing those safeties blow is one of the most exciting things about the hobby. It looks cool and sounds great. Reminds me that I am running live steam...........not a sparky. So now I run em hot, and just watch the water glass to adjust the axle pump to make sure there is always water in the boiler. Lot more fun (to me anyway) and everyone around knows its a real steamer, not one of those electric things.


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## Semper Vaporo (Jan 2, 2008)

Posted By Steve S. on 31 Mar 2011 09:43 AM 
Yes, alcohol is trickier to adjust the flame then with butane. I used to try and get the alcohol loco's flame adjusted to water being used, keeping the safeties from blowing off as little as possible. It was a real pain in the..............!!!!!! Then one day I realized that seeing and hearing those safeties blow is one of the most exciting things about the hobby. It looks cool and sounds great. Reminds me that I am running live steam...........not a sparky. So now I run em hot, and just watch the water glass to adjust the axle pump to make sure there is always water in the boiler. Lot more fun (to me anyway) and everyone around knows its a real steamer, not one of those electric things.


YES! I love just watching the rods go around and the valve gear gyrate (Engineer's side going away from me and Fireman's side coming at me)... but for some reason there is just no pleasure watching the simulated operation of a "Sparky" steam simulator do the same thing. Live Steam is where it's at!

And YES! The safeties blasting on and then sputtering a couple of times before snapping off is VERY IMPRESSIVE... First time it happened my machines was startling to say the least!... But on my Mikes they don't do that spectacular thing very often, (usually they just weep for a while then gradually increase the release of steam and then gradually close).


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## Charles (Jan 2, 2008)

Posted By iceclimber on 31 Mar 2011 06:13 AM 
charles, since I have my answer concerning steam plumes, what does cause certain beats in certain engines. Take the Britannia for example, a nice beat. Could you elaborate just a bit? I know the harder an engine worked, the stronger and crisper the beat. 
Jeremiah
Under normal conditions and with proper locomotive components (e.g. alignment & proportions of the blast nozzle(s), stack, and petticoat to give optimum steaming along with proper valve setup) remember that having a noticeable stack talk can be an indicator of poor efficiency. A quiet running locomotive is being more efficient. Yet, I do love the sound of a locomotives stack talk....


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## iceclimber (Aug 8, 2010)

I would have never guessed that the stack talk could be an indicator of poor efficiency. I guess I am for poor efficiency too if it means a better sound.... Thanks for that explanation.


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## ChaoticRambo (Nov 20, 2010)

Actually, a good sounding "bark" is not so much the maintenance of the engine (although that may be a factor), it is more to do with how much the engine is working.

The sound you hear from a steam engine is the exhaust from the cylinders coming out of a pipe in the smoke box aimed out the stack. This also functions as a source for good draft for the fire. The sound is always greatest when the engine is first starting out, or working hard. Typically, the more the reverser is open, the more impressive the sound because more steam is being forced out the same diameter pipe. This is why a steam engine at speed wont make nearly as much sound as a steam engine starting out, or on a grade.


Basically, the harder the engine is having to work, the better the sound.


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## iceclimber (Aug 8, 2010)

makes sense. When you say "the more the reverser is open", could you elaborate a bit on that? I am not sure I understand what is going on. I would guess that the johnson bar is notched back a bit so as to provide more valve lap over the intake ports? Or am I off the mark totally with that assumption?


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## Semper Vaporo (Jan 2, 2008)

Posted By iceclimber on 31 Mar 2011 01:46 PM 
makes sense. When you say "the more the reverser is open", could you elaborate a bit on that? I am not sure I understand what is going on. I would guess that the johnson bar is notched back a bit so as to provide more valve lap over the intake ports? Or am I off the mark totally with that assumption? 

When starting a steam engine, you apply the full boiler pressure to the cylinder for nearly the entire stroke of the piston, only closing the inlet just before opening the cylinder to the exhaust to remove the steam in the cylinder as the piston goes the other way. Residual pressure in the cylinder is lost up the stack (making lots of noise as it leaves). This is lost energy that didn't do any useful work.

After the engine is moving it takes less steam to keep it going, so you start closing the inlet valve earilier during the piston stroke. This allows the steam that is in the cylinder to expand in the cylinder, and thus doing work, and keeping more pressure in the boiler. When the exhaust opens there is less steam needing to escape up the stack and so it is quieter.

Moving the Reverser Lever closer to the neutral point shortens the stroke of the valve which is what closes the inlet port sooner, which saves steam. The semicircular guide ("Quadrant") that the Reverser rides on was notched so a pawl on the lever could hold the lever in certain places (long cutoff, mid cutoff, short cutoff, neutral and then the opposite of that for the other direction). When moved close to the center (short cutoff) the savings of steam, and thus a savings in fuel to keep the boiler hot was called "the Company Notch" because of the expense (cost of fuel, water and the Fireman's back) savings.


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## Dave Meashey (Jan 2, 2008)

As an additional note. The full stroke settings on the reverser (Johnson bar) were usually referred to as the "corners." To run forward, the locomotive was started with the Johnson bar in the forward corner. To start in reverse, the Johnson bar was set to the reverse corner. 

Yours, 
David Meashey


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## afinegan (Jan 2, 2008)

I haven't played with the reverser settings other than full forward and full reverse (notches in the johnson bar holder). I know some people who RC their Live Steam locomotives control the engine this way. (they open the throttle manually).
I heard in our small scale it does not matter as much as the 1:1 scale in which steam expansion plays a greater role (again, steam expansion doesn't scale down like we would want it to). 

Here is a neat writeup of what someone would have to do in order to run a 1:1 steam engine successfully. There are many Johnson Bar positions and its important to use them in a full size 1:1 steam engine.
http://www.trainorders.com/discussi...,nodelay=1

On a side note - a nice website on valve gears and how they work, and what the johnson bar does to each:

http://www.steamlocomotive.com/appliances/valvegear.php 


Andrew


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## rwjenkins (Jan 2, 2008)

The sound of the exhaust chuffs is another area where butane vs. alcohol firing makes a difference. Since alcohol-fired engines have a working blastpipe and petticoat, you'll usually hear a nice, crisp (if somewhat high-pitched) exhaust beat. A stock Accucraft butane-fired engine (like your much-anticipated K4, Jeremiah) has the exhaust tube crimped at the top with openings at the side, blowing the exhaust steam (and cylinder condensate and used steam oil) against the sides of the stack, and typically gives you more of a slushy "sssshh-sssshh-sssshh-sssshh" sound. But, since the exhaust steam is not needed for the draft, butane engines can also benefit from "chuff enhancers" such as the Summerlands Chuffer or the Cajun Bark Box, which give you a crisper, louder, and/or deeper chuff. These can make a huge difference, especially if your engine is working hard. 

For example, here's a "Greatest Chuffs" compilation video with my Bark Box equipped Accucraft K-27: 





... And here's a video of the same engine before I installed the Bark Box, with a lighter load on a level layout:


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## iceclimber (Aug 8, 2010)

So the bark box acts as a sort of microphone to the chuffs? More like yelling through a cone? I was told that making the loco work harder will enhance the chuff regardless of the inclusion of a chuff enhancer. I guess it will, but the chuffs do sound nice and crisp with the enhancer. I like it.


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## rwjenkins (Jan 2, 2008)

Posted By iceclimber on 31 Mar 2011 04:49 PM 
So the bark box acts as a sort of microphone to the chuffs? More like yelling through a cone? I was told that making the loco work harder will enhance the chuff regardless of the inclusion of a chuff enhancer. I guess it will, but the chuffs do sound nice and crisp with the enhancer. I like it. 
Yes, like yelling through a cone, more or less. It's all about the acoustics. With the Bark Box the exhaust steam is blown over a hole in a resonating chamber that fits inside the smokebox. The Summerlands Chuffer is another popular chuff enhancer which replaces the exhaust tube with something that looks like a whistle. It's not as deep in pitch as the Bark Box, but tends to be louder. Both are excellent products that sound great and will add a lot to your enjoyment of your engine.


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## Jerry Barnes (Jan 2, 2008)

I have a Summerlands Chuffer in my Aristo Mikado and really like it.


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## iceclimber (Aug 8, 2010)

Watching videos of the locos with the bark box/summerlands chuff enhancer make those enhancements mighty tempting. Something about it though just doesn't sit right with me. I mean no disrespect towards any that have these. I can't put my finger on the exact reason, but I do know it lies in the realm of after market mods. Either way, I like the sound enhanced. Guess I will have to wait and see what happens.

Thanks to all who "chimed" in on both subjects in this topic. I can say because of YOU I am a bit more knowledgeable in this highly addicting hobby. 



Please enjoy these two vids.

PRR K4 #1361



Britannia on the mainline


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## David Leech (Dec 9, 2008)

Jeremiah, 
If I may add another thought to this matter. 
As Charles and others have pointed out, on an alcohol loco the "proportions of the blast nozzle" is important, and will effect a lot of things. 
Imagine blowing at a candle. 
If you blow really hard, the flame is moved, and increased in intensity, and might even go out. 
If you blow soft, it is not so effected. 
On an alcohol loco, the blast nozzle is really doing the same thing, but is causing a sucking motion on the flames (don't try that with a candle at home!). 
If the blast nozzle is too small, you can cause the flame to actually pulsate with the exhaust blasts and 'lift' off the wicks and you will actually hear the flame 'flutter' like a pulse jet. 
But you will probably also get a crisper 'stack talk' 
Opening up the blast nozzle just a little will give a more consistent flame, but the stack talk will be reduced. 
Opening up the blast nozzle too much will result in the flame not having enough strength and poor running and lack of heat. 
DO NOT PLAY WITH DRILLING OUT YOUR BLAST NOZZLE unless you have a spare, or can make one. 
One hopes that the manufacturer has done it 'right', so you won't have to worry. 
It again adds another element to maintaining and running our alcohol locos. 
All the best, 
David Leech, Delta, Canada


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## iceclimber (Aug 8, 2010)

David, thanks for that piece of advice. If there is one thing I would probably never try, it would be messing with the diameter of the blast nozzle. While I can tinker around and am not put off with having to do some tweaking here and there, I am also aware of my limitations in terms of parts of the loco which could adversely affect the performance of the loco. Thanks again.


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