Hello Folks,

I just picked up Staufer's book "B&O Power" and there are a few paragraphs given to the idea of "front feed" stokers in the experimental section of the book.

In concept, I can understand the motivation and general layout, but are there any pictures of these contraptions? Agree that coking or clinkering in the screw tunnel could be a problem, if these were, in fact, run right under the grates.

Anyway, just a random request. I tried the search function but nothing really came up.

Happy Wednesday,
Joe

IIRC, at least some Santa Fe coal burners were equipped with front feed stokers. There may be some info in the 1941 Locomotive Cyclopedia.

I have not had the time to check, but this was apparently a hot topic toward the end of the Thirties (along with Steamotive), one of those things so unsuccessful in actual practice that even the memory of it has been rooted out. As I recall the then-fairly-new AAR was associated with the effort somehow --

One source I read indicated that as many as 71 B&O locomotives were equipped with a form of front-feeding stoker. This would have been a comparatively short interval, possibly early in WWII when photographic security was a little tighter, but still: the only potential source for pictures of the setup would be somewhere in the ranks of the photo traders. (As I never had much if anything worth trading, the depth of that resource is unknown to me...)

I cannot imagine that a road as chronically poor as the B&O would have made so large an investment in new technology if there hadn't been reasomably demonstrated results from test installations. (We can certainly have fun speculating on the reasons why it would be seen as such a rapid and colossal flop...)

Here's a rendering and description from the 1941 Locomotive Cyclopedia. It's a Standard FD type stoker at the bottom of the image.

What was the point of the FD stoker? To deliver the fuel from under the arch, to create a longer (potentially) combustion path?

Howard P.

Is that the stoker that had a glass (or similar) panel in the cab floor so the crew could observe the coal feed?

I recall hearing about some engines with that feature. was it the DM&IR 2-8-8-4's?

And what other engines were equipped with that stoker?

Precisely. Or a little more precisely, to provide the functionality of a typical throat-fired oil setup using solid fuel.

Running the conveyor all the way under the ashpan would have been suidical without modern nanoinsulation or the equivalent. Perhaps they theought it would nicely preheat the coal without supporting combustion if the dwell time got to be too great. Compare this with the fun with the chain grates on the N&W M-2 Automatic and then the TE-1, where rolling out the partially-ignited coal was less involved and for a shorter distance...

Even with relatively automatic jet and coal-flow characteristics (see some of the patent lawsuits about stoker distribution-plate design) it's going to be tough to figure out how the plume ought to be fed, or how much of it needs to 'drop out' to maintain the right firebed over its length, or prevent fines or ignited lumps making their way 'around' the nose of the brick arch for longest TOF from grenading against the firedoor or observing glass... better be sure it's quartz, or the right kind of isinglass... ;-)

Lo and behold, the FD remains illustrated in the '47 Cyc (on page 403) where it is described as being developed from the MB stoker. They cryptically note that the conveyor is extended 'under the mud ring and the grates'. I see no indication of insulation on the part of the conveyor enclosure that goes beneath the whole length of the firebox...

See also here:

https://sfrhms.org/wp-content/uploads/2019/08/SteamLoco-5.pdf

The Santa Fe's take on the type FD begins on page 165. Note the item about keeping the steam jets off when 'reading the fire' to preclude hot coals in the face...

I can imagine the steam jets on the stoker table with this arrangement would consume less steam than with a normal firing arrangement. The stoker is distributing coal in the same direction the draft is already flowing (towards the rear of the firebox before turning upward around the arch). So lower steam flow should be sufficient to adequately distribute the coal since you’re not trying to propel the coal particles against the air flow. This would be doubly beneficial, as you’re reducing the steam consumed by the stoker, and you’re injecting less steam into the exhaust gases above the firebed. The steam injected here has to be drawn through the tubes which is a loss for the drafting system (work done to move waste steam instead of combustion gases).

Likely the other obvious drawbacks outweighed the possible gains I’ve suggested.

I looked at some of their patents (Google says Standard Stoker Company had over 650 patents.) I found a couple of patents for distributing the coal from the center of the grate. Their reasoning for that was the draft and the velocity of the gases was greatest next to the backhead. Which entrained the smaller pieces of coal in gases instead letting them fall onto the grate. Tom Hamilton

https://patentimages.storage.googleapis ... 302412.pdf

Dead link

There was a typo in the link as I entered it: that should of course be an 'L' in loco instead of a colon. I'll correct it in the original post.

https://sfrhms.org/wp-content/uploads/2019/08/SteamLoco-5.pdf

The advantages of firing from the throat are well established for oil firing, and a good case could be made (or perhaps I should say as good a case as possible can be made) for PC firing from the same general location.

The first problem is that the approach is only going to work with good coal, properly sized and perhaps even classified just before distribution. That is NOT going to happen in the 'sausage' of a typical MB stoker feed up to the distributing table! (See Wes Camp's comments in general about the characteristics of that charming piece of equipment...)

However, oil firing almost pre-carburetes the fuel stream in the first couple of feet of 'flight', and the excursion around the arch and back under the crown involves what is mostly a vapor (either fully-vaporized hydrocarbon or suspended relatively-small globules of progressively higher carbon content, for luminous flame, that easily follow the flow streamlines in the combustion plume). The is NOT AT ALL true of coal shoved out of an MB-style 'elevator' -- hence the comment in the FD operations about keeping the firedoor closed when the stoker is feeding.

More later.

The B&O Summary of Equipment, dated January 1, 1948, lists a total of 64 locomotives equipped with a Front Delivery stoker. There are seven in the "Q" sub-classes, with the remainder scattered in the "P" sub classes.

JR