MEG Wendy on Coal

[ChipsAhoy]

I've got the frame done, drivers, "J" boxes, axles & cylinders. And now begining work on the gizmos inside the frame, and the valve gear.
Thinking ahead a little, I have the boiler pipe cut and in hand along with the firebox. Being a Marine type boiler, the firebox is simply a smaller dia pipe inside of the larger boiler pipe. There are no formal water legs nor air intake beneath. All the air is to come in from the rear end of the fire box. The grate will be about a third of the way up from the bottom. So the question...
Will the air adequately supply the front of the fire? Or does it have a tendency to burn only at the free end? And another point.... A more conventional loco boiler, compared to the marine boiler, has a tremendous amount of surface area for heat transfer from the fire box to the water. The marine boiler effectively has only the upper third of the firebox for direct heat transfer.
Anyone have good experience with a coal fired marine boiler?
Anyone with a Wendy, Sweet William or the like have first hand knowledge?
Or, anyone have thoughts on the subject.
Good ideas to modify the firebox design to do a better job of burning coal?
The concern is it all may work fine as designed, here at the realitively flat terrain of Maricopa, but will the Wendy supply adequate steam for the more hilly railroads with a coal fired marine boiler.
All that being said, I intend to make her dual fuel. Hopefully run coal when I want to operate the engine, slide out the grates and slip in the propane burner assy and turbulators, when I want to play trains.

Scotty

[Fred_V]

I had a friend with a Meg with marine boiler. It steamed well but he did have to rake out the ashes often due to the shallow ashpan.

[ChipsAhoy]

I had a friend with a Meg with marine boiler. It steamed well but he did have to rake out the ashes often due to the shallow ashpan.

Oh yeah.... no ash pan.
I just went back and glanced over the plans again. It appears that the cockpit floor has a sloped chute in the center where one would rake the ashes out and back from the firebox and then out the bottom. More to think about.

[James Powell]

I'd think Harlock will be best placed to answer this, but the one that is here (VIME) runs regularly on coal, on up to 2% grades. The grades aren't that long, in that the property is fairly flat. As to how it will do on a really long hard grade, I can't answer, and I don't think the owner is online much if at all. Dad has been mucking around with one in Ontario, and the preliminary is that having a grate as long as the firebox makes a fairly healthy difference to the steam production.

The one here had a rake for under the grate, a sort of moon shaped thing that I think is used fairly often. (it's used enough that it stays with the engine...)

James

[Fred_V]

James is right. Make the grate full length. If that isn't enough make the firebox longer. I would think there is no reason for it to not steam well.

[Harlock]

I have been running my Wendy mostly on coal for the past 8 or 9 years. It fires very well as long as you use good fast burning coal. Australian char was the best, but expensive. Bill Dobbs still has some for sale at Train Mountain from what I understand.

More recently I tried Hesperus coal from Colorado, the stuff is awesome. Smokey but awesome. Burns very aggressively. I can pull about 2,000lbs of train up 2% and pop-off when I hit the top. Pochahontas or similar bituminous should also work well. The only coal that didn't work was low volatile smokeless blacksmith's coal, there is not enough fire volume for it to combust properly. It burns too slowly, in a nutshell. With the smaller fire volume of the marine boiler you need more energetically burning stuff. Same experience on a friend's MEG Uncle Sam as well. that an anthracite, which was just too hard to get lit and stay lit, even when blended with soft coal.

I do not have a full length grate, it is about 3/4 of the way through with a vertical arch. Will post some pictures. I don't see how a full length grate could work because it would just clog up all the lower tubes, and you'd get very little air flow.

I have a crescent shaped rake to rake out the ash into an 8X8 baking pan, then I dump that into an ash pit later. Works well and I rake it a few times a day when running all day, depending on the fuel. Our cab deck was not made with the hole for the chute, although the chute is there as a frame spreader. We initially envisioned running it on propane so that's why the hole in the floor is absent, never bothered to put it in. If I planned to extensively run coal in the future I would put it in.

Regarding air intake, no it's not a problem and the entire fire bed will burn well. Oddly enough, the opposite of what you theorized is true when firing up. The fire starts at the front and works its way backwards, probably because the heat heading forward with the draft is helping it. Also, having some ash at the bottom helps act as an insulator - the water at the bottom isn't cooled by the air flow as much. I leave the ash in till it gets pretty high. acts as a damper and seems to retain heat better when ashed up a bit.

Changing out coal for propane in the MEG is very easy, as it all comes out from the back. I can change back and forth in maybe 20 minutes.

Don't forget as far as heating, the fire bed also heats the sides of the firebox as well, so there is a lot of transfer going on. I'd say more than half the shell diameter is getting good heat, from the bottom of the fire bed to the top of the crown sheet. The firebox is surrounded 360 degrees by water, so it is much better than say a briggs boiler.

Although running on coal is really fun, I am designing a new propane burner because I'm tired of perpetually cleaning up the mess at the end of the day. I've got a new design that takes advantage of all 360 degrees of heating space. Will probably post about it once I have the prototype built and tested...

-M

[SZuiderveen]

I have regularly operated the Wendy at Chesapeake and Allegheny in Baltimore. When firing up from cold the fire tends to stay at the front and is hard to get established in the rear, basically because the quickest path of air to the smokebox is the front part of the grate.

I’ve tried a orange slice shaped baffle on the end of a poker halfway down the ash pan for the cold fire up, but usually it’s too much trouble and we just deal with it. Once you get a good half mile of public running going everything is good and hot in the firebox and the ash pan and there is no problem keeping a fire. Sometimes we do have problem with carrying ash over the arch and filling the lower flues.

Edit: just read Mike. We burn a Pocahontas variant in our Wendy.

Steve

[ChipsAhoy]

Now that is very interesting, the better burning in the front. Antisipating having a problem, we were contemplating a pair of air tubes routed upwards to the front of the firebox. In a inverted "V" up through the boiler shell, through the water and dumping at or near the end of the grate, with a diffuser on the firebox ends, much like a halon fire nozzle or a water nozzle used to wet down a roadway. Glad you guys elected to share that info!
We have a large supple of donated Pocahontas coal here, and Maricopa Live Steamers sells it as a fundraiser.

Mike, I am very much interested in seeing your propane burner design when completed. I was toying with trying to use Marty burners, but it appears that by the time I make a manifold and fasten even a stubby version of one of the burners, my flame would be so high it would impinge on the shell. For right now I will build one like the original plans show.
The arch that you have, do you have a rudimentary sketch that you can share?

Steve, the "orange slice", do you mean that you were attempting an air dam or weir? You gave up because of the trouble, but did it seem to help? Something that might be perfected?

Scotty

[SZuiderveen]

Scotty

Yes, block air temporarily to front to get rear to light. Saves maybe 15 minutes on fire up. Once everything is good and hot in operation this is not so much a problem, as the draft moves the coal from back to front.

Steve

[Harlock]

Like Steve said, once it is lit, no problems, makes good fire everywhere.

No worries on making any special air tubes or siphons. You can use the moon shaped rake as a damper as Steve has done, JIm Sabin does this with his Uncle Sam.

When I fire up I don't bother, just turn the blower up and wait after lighting the coal with a MAP gas torch. (I got tired of using wood or charcoal or soaking things in kero, torch is easy cheating...)

Regarding MartyBurners (which are similar to LocoParts / Solarflo burners) they should work, Jim Sabin made a burner manifold with two rows of Locoparts burners 14 total. I think if it had a third row it would have good power. (21 burners) I found it a bit wanting with 14, but then I have a big train, and it was even heavier at the time with the log cars. His are angled at 45 degrees by orienting the square tube same. they play along the walls a bit. Here's a picture. They have quite a bit of baffling, seems to work in this case. I borrowed them for use at Train Mountain one time. The last picture shows them operational in my loco.

I'm doing a burner based off Lindsey MacDonnel's hole burner for Ernie Beskowiney's engine. It has a pre-mixer like the stock meg burner but I think this one will be a little more efficient for the available area. We shall see. I like that style burner because it's super quiet and lots of BTU per square inch and low combustion height.

Did not have time to photograph my grates today. Perhaps tomorrow.

-mike

[Harlock]

Here's the coal grates. As you can see they're just about worn out in the middle and it's time to turn them over. It also shows you where the fire is the hottest, again a little towards the front. They are stainless grates, but the char burns so hot it wears them out anyway. The vertical arch at the front end goes about 2/3rds of the way up. The air inlet is about 1/5th of the total circle area, and starts at the bottom of the grates. The tool for raking the grates is shaped like that opening in the first photo. less tall than the opening so you can lift it up on the way in, and then drag against the bottom. I think the rake tool is in my trailer off site as I could not find it for a photo.

The last photo shows the boiler without the grate insert. If you were to put grates right up to those tubes, you end up blocking a bunch of them with ash, probably from the top of the fire on down. The tube nest spans the entire firebox from top to bottom.

[Harlock]

Here is a rendered view of the boiler, showing how far burners or grates normally extend. This was an earlier set of burners, not Jim's from above. These were very cheap impingement burners. (it was a failure - too noisy and not enough power)

There is about 4" of space between the vertical arch and the tube pate, leaving around 9" of usable length for grates or burners. Might be able to get away with less, but probably the less gap you leave, the less the lower tubes will be utilized.