[darwins]

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The whole fire mass thing is weird as I've never heard of a fire being measured as a "mass", which in the simulator can be up to a few tons in some cases!? (Coal is heavy but not that heavy, how much do they expect us to cram in there?)

For a solid fuel fire, the simulator needs some way to know how much fuel is in the firebox.

Are the values unrealistic?

For a medium sized British loco if we take the bulk density of coal as 800 kg/m^3, and a grate area of 3.00 m^2, and a depth of coal on the grate as 0.20 m. Then we get a volume of coal of 0.60 m^3 which would have a mass of 480 kg - around 0.5 tons.

This is the kind of value that I get in ORTS - so in my opinion the values themselves are realistic.

One problem that I see is the focus on "ideal" fire mass. The basic logic is good -
if the fire is too thick then it will restrict the flow of primary air through the grate and less heat will be produced;
if the fire is too thin then when the engine works hard the air flow might be too fast and lift fire from the grate.

In real life an engine with a hard task may be run with a thicker fire (maybe 15-20 cm depth of coal) but working a lighter train or coming to the end of the day the fireman might run with a thinner fire (say 8-10 cm depth of coal). The "ideal" depends on the work being done. (Locos with mechanical stokers I believe run with a thinner fire than hand fired locos anyway).

For any solid fuel fired loco there will always be some mass of fire producing heat, regardless of feed rate. (Dampers help to reduce this.)


For an oil fired loco fire mass = 0. By reducing the feed rate then the amount of heat going into the boiler can be reduced significantly and rapidly.

[Laci1959]

Hello.

I'll give in. Have secondary air. But there is no firebox door in that picture, it is clear that it was dismantled. Because it is an oil-fired locomotive from the stock of the Budapest Railway History Park. Permanent secondary air was set up.

The video below is an old tutorial video. It is played by actors, but some scenes were filmed with real heaters and train drivers. At three minutes you can see a charcoal shovel firing. At the 11th minute, several shovels add coal to the fire before closing the door.
Oh, and there is no flap on the door, this is also noticeable.

https://www.youtube....h?v=y-eFRX6VBkU

Sincerely, Laci1959

[Laci1959]

Hello.

What about the combustion product? With the accumulated slag? You don't take that into account for the primary air? I know it depends a lot on carbon.
Or is this still the distant future? Once maybe.

Sincerely, Laci1959

[darwins]

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What about the combustion product? With the accumulated slag? You don't take that into account for the primary air? I know it depends a lot on carbon.
Or is this still the distant future? Once maybe.

I think it is all just distant future. Maybe one small thing at a time.


ash = small, in the ashpan under the grate and

clinker = big, in the firebox on top of the grate

will both reduce the airflow on a long journey.

We could model this effect by reducing the effective grate area with time. The question is how much? Low quality coal produces a lot more ash and clinker than good quality coal. Do we need to add more parameters to the fuel description? %carbon, % volatile, %ash....?

Is there any data available?

The best I can do is to make a guess based on some very crude information.
The GWR King (grate area 3.2m^2) was designed to run up to about 350km (4 hours) without change of loco.
The LMS Princess (grate area 4.2m^2) was basically the same engine, but intended to run up to about 700km (8 hours) without change of loco.
We might therefore guess that solid combustion products reduce the effective grate area by about 20-25% over 4 hours.
So maybe about 5% per hour based on good quality Yorkshire or Welsh coal with 5% ash content.

[ South Kirkby coal = 13717btu/lb moisture 3% volatiles 36% fixed carbon 56% ash 5% ]
[ Markham coal = 14360btu/lb moisture 1% volatiles 19% fixed carbon 73% ash 7% ]

Both of the above were considered "Grade 1" coals used for the best express passenger locos.

Analysis for a "Grade 3" coal used for goods locos gave
[ Blackwell coal = 11800btu/lb moisture 4% volatiles 38% fixed carbon 48% ash 10% ]

[P Escue]

I’ve found that the addition of ALT+H, CTL+H, and ALT+CTL+H to the AI fireman is a major improvement. One of the main things lacking the AI fireman was that it only reacted to what was happening now, with no anticipation of what was needed ahead. Where ALT+H to increase the firing for approaching a hill and then cut it off with CTL+H and then watch the boiler pressure and reset it back to normal with ALT+CTL+H when the pressure is where you want it maintained works well. Also cutting firing when you are going downhill helps save coal.

Fire mass was back in MSTS days. I always felt that it was something you could use to judge what the fire was doing since you could not “see” it. The ideal fire mass was the target for having the fire at its best and the actual fire mass was what was happening with the fuel.

I, to would like the see water level affected by the gradient, but if it is, you may need a way to increase/decrease/reset water (injectors) for the AI fireman as well.

Still, I would like to know how CTL+R affects shoveling. Does it just add an extra scoop of coal each time you press it, but doesn’t affect the rate of shoveling? I’m not the best manual fireman even with MSTS (found being the engineer, fireman, brakeman, and conductor was a little too much). The others I can handle but adding the fireman on top of it is just too much (for me anyway).

Phil

[darwins]

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Still, I would like to know how CTL+R affects shoveling. Does it just add an extra scoop of coal each time you press it, but doesn’t affect the rate of shoveling?

Just tested to find out the answer. CTL+R adds a shovel of coal in addition to any "mechanical stoker" rate that is already set. It does not change the stoker rate.

[P Escue]

Thank you,

Phil