Why does the fireman add sand to the firebox on an oil burning steam engine?
In a nutshell, it helps clean out the flues.
hmph. How much sand?
Not much – note the size of the tender box and the little ‘dipper’ used to dispense it.
Sand at draft-air speeds is an efficient sandblasting agent, and the petroleum buildup in the tubes is comparatively soft (unless there’s vanadium or some other weird stuff in there… but that’s another, longer, MUCH more boring story…)
Well that makes a lot of sense
you’d wanna keep those clear to produce the hottest fire possible
wonder if anyone ever let them get too clogged and the smoke backed out the firebox doors
Think about it a moment.
Would the burner continue to work correctly with the draft cut off, or would it start dribbling flaming oil? I believe we’ve had a couple of threads depicting in rather delightful and grisly detail the various kinds of whoopee that ensue when smooth draft on an oil-burner starts to be interrupted…
I remember all the hub bub about the 4018 movie and one story behind the movie was a kid who loved the engine stole it so it couldnt be scrapped. Yeah just gonna hop up in there and get 300 psi real quick and just put that sucker in drive. I read on another board how a guy started an oil burner up from cold pretty long and drawn out process. I imagine being a fireman is an intense job I cannot even imagine trying to train on how one does that.
The flues should be sanded frequently enough that a significant reduction in draft isn’t an issue. The fireman will balance fuel, atomization (i.e., the vaporization of the fuel by means of steam jets at the burner) and draft in order to produce the most efficient fire. A fire which is burning on too rich a fuel mixture will show up immediately in black smoke at the stack . (This sort of thing is done deliberately to impress photographers.)
Probably the more important reason for sanding flues is to remove deposits in the flues which impede heat transfer to the water surronding the flues in the barrel of the boiler.
A coffee can’s worth of sand, which will be sucked through the firebox and flues in matter of several seconds, will probably suffice for a relatively small boiler, when administered once or twice during a typical trip. Experience is the guide here.
I’ve seen a scoop holding about 2 U.S. quarts used on a CPR 2-10-4 Selkirk. There was no need to pour the sand in , the fireman just opened the small porthole in the main firedoor and held the scoop mouth near the opening and whoo***he sand was gone in a fraction of a second! In another fraction of a second sooty sand and smoke blew by the cab window.
I’ve read about a firemen on a coal fired steamer having his shovel sucked into the firebox by the draft, also another fireman losing his prized railway pocket watch that way.
There’s a great story on Steamrailroading.com called “How to Boot a Steam Locomotive” , which tells about a museum volunteer firing up a locomotive from dead cold until it was ready to move out-many hours. Here’s the link:
http://steamrailroading.com/ipw-web/portal/cms/index.php
[:)]
Really good article, I remember reading that quite some time ago.
A handful or two of sand is often thrown (or sucked) into the firebox on run bys for foamers. The sand scours the soot from the flues and makes a lot of black smoke. Residents along the line are not too happy about this. We lived near a B&O line in the 40s and 50s. In the days before clothes driers you would time hanging out the laundry to be between trains or the laundry would be spotted with soot.
Also get the same effect on clothes lines from coal burning loco’s if they start to prime - then you have loads of sooty water flying everywhere!!
I’m curiouse what happens in an oil burner if under a heavy load and firing rate, the throttle were suddenly closed like in an emergency stop? What about in a tunnel?
In any steam locomotive, if a flue joint fails, would the steam escape through the fire box?
jruppert, there have been other threads on this point. What happens when you have to make an emergency stop is this: The fireman cuts off the main oil feed as soon as possible, before the engineer has cut the throttle far enough back to reduce draft and cause problems. There is usually enough time to accompli***his before the brakes have started to apply, so there’s no problem in the engineer ‘setting the air’ before working throttle and cutoff.
There may be a bit of afterflow when the valves cut off, which may result in oil drooling down into the pan, but I don’t think there is substantial roiling black smoke, firebox explosions, etc. as a risk. Restarting that locomotive might be a whole different story, but not the story you’re asking about…
Naturally, in a tunnel you get severe problems with smoke and heat, much as in a coal burner but with different constituents in the smoke. It is considered wise not to sand flues while in the bore! Note that the SP cab-forwards got around the issue in a very sensible fashion (which the use of oil fuel essentially made practical in the first place!)
When a flue or tube joint fails, the steam will escape from anywhere it can. Naturally there will be more steam evident in the firebox if a rear tube joint leaks than if it’s a front joint; but remember also that any draft, including blower draft, will be pulling combustion gas of much higher mass flow forward to the stack, and much of the steam can be expected to flow forward, rather than ‘into the firebox’ against that draft.
Note that it was routine for locomotives to work over the road with failed flue joints (at reduced efficiency), and for these joints to be plugged rather than properly fixed to put the engine back in temporary service. You can readily recognize that this wouldn’t be possible if there were large quantities of steam in the firebox!