[copperpen]

UK footplates are not large so the fireman would not have far to move. On the smaller engines he could stand between the tender and firebox and just swing the shovel round between tender and firebox. As for leaving the firebox doors open, not happening.

[atsf37l]

That is my experience on US Narrow Gauge locos as well - assume the proper position and swivel in place from tender to fire door to tender, with the door opened only as the scoop approaches then immediately closes between shoveling strokes.

[Weter]

Prolonged keeping fire doors opened cools fire significantly, suppressing burning and heat production. It could be neccessary in some cases of "oxygen starvation", or emergency quick heat reduction, but at the rest, I'd assume that mostly unwanted.
Also, I'd suppose decreasing of air flow through solid file's fuel layer from bottom (grate grills), and, since coal slag is meltable, involving cooling from the upper side by fresh air going from opened firedoor, the solid film can appear, closing spaces between coal pieces, what would cause further fire degradation.
Sudden and deep heat temperature drop, caused by massive cold air's flow, plus fire cooling and degradation, are able to cause significant stress to firebox metal walls, ceramic coating, so cracks might appear.

[Traindude]

copperpen, on 22 June 2023 - 09:31 AM, said:

UK footplates are not large so the fireman would not have far to move. On the smaller engines he could stand between the tender and firebox and just swing the shovel round between tender and firebox. As for leaving the firebox doors open, not happening.

I think that in the case of those locomotives where the cab-to-tender distance is relatively short, then the delay between "scooping up" and "tossing in" can be relatively short (no more than maybe 1-2 seconds), whereas on larger locomotives where the distance is greater, then the delay can be longer. Again, this is something that would be specified by a new *.eng file variable.

As for the fire doors, I'm VERY confused: Yes, I am aware that leaving the door open too long can have adverse effects of the fire and the firebox, but IIRC, in the aforementioned "Little and Often" training film, the narrator says something along the lines of "Adjust the [ fire door opening ] until you get light gray smoke at the chimney." They also described how the secondary airflow comes through the fire doors.

So, in revising the UK model, should the fire doors be closed after every shovelful or at the end of the firing interval?

[copperpen]

Fire doors are closed between shovels. After firing is completed the admission of secondary air takes place. Some locomotives had adjustable air intake with fire doors closed. The addition of secondary air was to add oxygen above the fire to burn off hydrocarbons generated by heating the coal. After this is completed, the secondary air source is usually closed to maintain heat in the firebox.

[darwins]

copperpen, on 23 June 2023 - 02:50 AM, said:

Fire doors are closed between shovels. After firing is completed the admission of secondary air takes place. Some locomotives had adjustable air intake with fire doors closed. The addition of secondary air was to add oxygen above the fire to burn off hydrocarbons generated by heating the coal. After this is completed, the secondary air source is usually closed to maintain heat in the firebox.

Fire doors on most locos could not easily be closed by the fireman between shovels at least on most locos. See Little and Often. Time between shovels is less than 2 seconds! (Some later LNER and SR locos may have had a foot pedal operated US style firebox door.)

@Weter - too much cold air will damage the tubeplate - but secondary air either through opening the fire door or through vents in the fire door or separate vents is usually needed for complete combustion - especially if the coal has a high proportion of volatiles. The air flow through the fire door is presumably not enough to cause damage with a good fire in the grate.

[Weter]

Yes, I agree, as firebox is quite long. I also appreciate Mervin's(?) notation, and Your, Darwin confirmation of that. Indeed, primary air is not enough for completely deal with volatiles, but in both of your replies there's a principle moment: not whole firedoor should be opened continuously (what brings massive and slow portion of cold air, interrupting fire), but some kind of smaller openings: either special vents, or partially closed firedoor. And those thin and fast jets of air are effectively blending with fire, quickly taking heat and burning excessive volatiles, extracting more chemical energy of fuel to heat.

[Traindude]

In regard to the admission of secondary airflow to the fire, I didn't notice that most fire doors had vents and baffles to admit secondary air even when the doors are completely closed.



Here's a drawing showing the common American "Butterfly" style pneumatic fire door. Each door plate has built-in vent holes on the cab side, while the fire side has several holes close to the edge of the door plate. The result is that the "staggered" spacing of the holes on each side force the air to make a more circituitous route before going into the firebox. This action also cools the door plates, preventing them from overheating. I wish I could illustrate the path of the airflow on this drawing, but that's easier said than done when you have only 2 dimensions to work with!

So in terms of adding new fire parameters, the minimum secondary airflow (with the fire doors closed) should be specified with a new *.eng parameter.

Also, note that the hand lever guide (pneumatic fire doors also had the ability to be opened by hand, even though the handle does not move when the door is opened pneumatically) has a "smoke" notch in it that keeps the door "cracked" open to let in additional air to clear up any dense smoke that may develop.

[Weter]

I agree, that holes are primary for cooling the door plates and, that way, to return the heat, it takes - back into firebox, by the air, suctioned through holes.
I agree too - that narrow opening is useful in some cases.

[ATSF3751]

I just wanted to Open this thread back up and would like to get some conversation going again. A few things I would like to see when it comes to steam locomotives in Open Rails is as followed and yes I am aware some will take quite a bit of coding.

1. Two different smoke versions. One for Smoke and one for Steam. The smoke would be for the exhaust out of the stack and the rest like dyno, cylinder cocks, booster, air pumps and any other features that steam locomotives have.

2. The chuffing of the steam locomotives to be in sync with the wheels and sound.

3. We also need better smoke to be produced and have it interact with the puffing of the locomitive instead of just flowing out of the stack and blowing all over the place.

4. Better automatic and manual firing for fireman.

Yes I do understand some of this is not possible at this time but something to look at for the future.

Brandon