I don’t know how it occurs but I see smokers do it all the time.
Great how to article…Took me a long time to figger all that out years ago…neat thing is two locmotives of identical classes may not have the same fitting layout…really was kinda a Shop specific thing…
My God, these guys were geniuses! In the movies, the hero jumps in the cab alone and rushes off to save the heroine!
Yeah, right.
Lou Luczu said:
My God, these guys were geniuses! In the movies, the hero jumps in the cab alone and rushes off to save the heroine!
Yeah, right.
Kinda like in this season’s opener of Hell on Wheels where Bohanan fires a frozen solid engine alone and rides off down the rail. Good drama, but couldn’t happen.
Yeah, but now I can tell it’s a wooden engine, and they don’t freeze. But how do you light a wooden firebox?
Very easy to light; difficult to keep contained:]
Sorry for derailing your thread Dave. Great pictures and I learned a lot about stem piping
I apologize too, I got easily distracted.
I still can’t believe you can remember all of those pipes and valves with no labels! Well done.
When we fire her up from cold (ambient 65deg) it takes about 5 1/2 hrs in Silverton because we don’t have a good compressed air source to run the blower. In Chama this week it only took a little less then 4 till we hit full steam as they have a big air source to run the blower on, all the time.
Alright who’s the math genius out there. We have about 25,000 lbs of steel in the boiler with tubes and all, and right at 1200 gals of water in the boiler. Assuming 65deg F cold, How meny BTUs does it take to get to 165 psi? Remember that, the higher the pressure the higher the boiling point of the water. so as the water starts to boil and create pressure the hotter the water has to get to boil to create more pressure.
ugh, I tried to remember my Thermodynamics and I am drawing a blank. I even tried looking up some stuff and I cant remember.
I can tell you that based on steam tables the boiling temp of water at 165 psi is around 370 degrees F.
It takes approx. 8.33 BTU to heat 1 gal of water 1 degree.
If everything was a closed perfect system you have 305 degrees to bring your water to temp. So…
305 x 8.33 = 2,540.65 BTU to heat one gallon of water to 370 degrees. To heat 1200 gals…
1200 x 2,540.65 = 3,048,780 BTU
Now you have to calculate what it takes to heat that metal to get the water to start heating up also…
The equation is (I had to convert stuff to Metric for the calculation, but converted back after.)
9,331 kg (weight of steel) x 0.49 kJ/kg C (Specific Heat of Carbon Steel) x (187.78 C - 18.33 C)
= 774,757.6 kJ or 735,245 BTU
There is more to do with heating the water to the 165 psi but that is where I got stuck. But as you can tell it takes a lot of BTU to get the old girl heated up. Considering that The BTU of Anthracite Coal (which I assume is probably close to what is used in the loco) is 26.27 million BTU / ton.
Also like Dave said there is a changing environment from no pressure to 165 psi. SO the boiling point at first is 212 degrees and steadily increases as the pressure increases.
Sorry, that’s all I could remember about Thermo.
I think the technicnal term is…“a crapload”
Wow, thanks for the lesson on steam loco controls! Very informative, and will be helpful whenever I get around to detailing the backhead on one of my models.
Also, that shot of the loco blowing smoke rings is too cool! I didn’t know that was even possible.
Jake, A whole lotta thanks for the math.
So if I get this right. It takes about 3.784,025 BTUs to get her hot. At about 26,27 M BTUs per ton, then it takes about 285 Lbs of coal to fire her up. Oh ya, and wads of paper, oily rags, and scrap lumber to get the coal to light.
Approximately Dave.
Keep in mind I didn’t take into account atmospheric conditions. You know as well as I that if it is a cold drizzly 65 degrees it will take more than a sunny 65 degrees.
As I sit here and think of only 285 lbs of coal to heat up 25,000 lbs of steel that just doesn’t seem right. I would think it would be more…I would guess at least 10x more than that.
I would think it would take more. First we can account for more if we consider that the firebox is definitely not a perfect system. Not all of the heat from the coal is transferred to the steel. If that were the case and I estimate that it takes 10x more coal to heat the steel. Then…
efficiency factor = 285 / (285 x 10) = 0.1 or 10% efficient. Is that right???
Follow-up…after more research.
According to The second Law of thermodynamics. The maximum efficiency of coal is 77%.
As I looked deeper, many will use the heat transfer efficiency of coal at 30% and that is considered in an ideal situation.
What I mean by heat transfer is the ability of a substance to generate heat into another substance. In other words, the potential BTU from coal is 26,270,000 BTU. However, when lit by fire, the transfer of those BTU to work is significantly less.
Since most calculations for the thermodynamics of coal has an estimated 30% efficiency (Ideal situation), then in the non-ideal situation of a locomotive firebox, the the efficiency of the coal could only be 10%.
Jake,
Is wood even less efficient to fire a steam engine than coal?
The second law of thermodynamics says the maximum efficiency of wood is 55%. So yes wood is less efficient than coal. Also, as I stated before, the 55% number, along with the 77% in coal, is a perfect system and that doesn’t exist in the “real” world.
I have no real data to back up my guess, but I would venture to believe that the heat transfer efficiency of wood in a fire box to be below 10%.
Also, think about the potential BTU of the fuel. Coal you already know. I look up the potential BTU and it ranges from 13.00 million BTU/chord to 29.00 million BTU/chord. Guess what is considered the best BTU?
Hickory, It also has a low smoke and low spark. I would think that would be ideal in a locomotive firebox.
All this makes me understand why it takes more wood to fire a locomotive than coal. You have to burn more to get the potential energy needed to operate the locomotive.
Back to the math.
Splitting the differance of the thermal efficiency of coal of 30% to 10% set. I used the 20% guess.
Coal BTU per ton of 26,270,000 x.20 = 5,254,000.
Giving a extra 50% BTUs for the steels thermal transfer rate from the original amount.
Steels BTUs needed to heat to boiling, 735,245 x 2 = 1,470,490.
BTU’s needed to boil the water 3,048,780.
Water + Steel 3,048,780 + 1,470,490 = 4,519,270 BTUs
Needed BTUs 4,519,270 / 5,254,000 Coals usable BTUs per ton = 86% of a ton
A Ton of Coal 2000 lbs. x .86 = 1720 lbs to fire her to steam.
NOW that seems to be a better number.
Too much math for me. 
Looks good to me Dave. Almost a ton of coal to fire a small steam engine seems appropriate.
Worked thru a few more photos from our excursion with 315 on the C&T.
From the Night photo shoot I put on. 315 with part of her crew as models.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/_MG_2552_zps84a68e66.jpg)
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/_MG_2576_zpsaad96c6a.jpg)
315 outside of Antonito climbing to Lava Tank with a string of cattle cars.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/_MG_3261_zpsf78bb3c5.jpg)
315 working her way up grade in the Southern Rockies towards Osier.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/_MG_3364_zps5b0975cc.jpg)
And 315 pulling hard.
(http://i1234.photobucket.com/albums/ff403/dave2-8-0/_MG_3994_zps31ea100d.jpg)
Enjoy.