Identify this steam tender "control" please?

[mmagliaro]

In the photo below (it's a Walthers 0-8-0), what is that little pipe sticking up in the back
of the coal bunker?



It's not present on all tenders, but seems to be on NP ones a lot.
From drawings, it is shown as a pipe extending down to the bottom of the coal bunker, so
I am guessing that somehow it is a control for the auger to move coal forward in the tender,
but I really have no idea.

Anybody know?

Thanks!

[Chris333]

Air powered coal pusher.

[SkipGear]

http://www.schenectadyhistory.org/railroads/manuals/slsb/03-100.jpg

Part of the stoker system.

[mmagliaro]

Thanks for that great photo and diagram reference, Tony!

But I still don't understand.  How would the fireman or other operator get back there to
touch this thing while the engine is running?  And even if they could, why would such a device
be designed to be back there in such an awkward location?

Chris, you say it's "air powered".  How does it work?  Is it  an air-powered "motor" that connects to the auger via a chain drive, that just sits back there and
runs, under control of an air valve from the cab?   It kind of looks like it might work that way from Tony's pictures.

[hunter_alexander]

The fireman can turn it on in the engine. It is just an air powered motor that turns the drive for the stoker screw in the tender.

[Chris333]

It is a big blade pushed up and down by a cylinder that is air or steam powered.
http://www.dukeofgloucester.co.uk/?page=Heritage+Lottery+Fund+Project

http://books.google.com/books?id=hhwXAAAAYAAJ&pg=PA138&lpg=PA138&dq=air+powered+Coal+pusher&source=bl&ots=wMtaTBkydJ&sig=ST8W36NT6aGBc6PIeDu3fP_tv3o&hl=en&sa=X&ei=jhryT-HTKobe0gGWhYD8Ag&ved=0CE8Q6AEwAA#v=onepage&q=air%20powered%20Coal%20pusher&f=false

The photo Tony posted is the lifter inside the cab at the end of the stroker. That dumps coal into the fire box.

The Duplex Stoker occupies very little room in the cab, since it has only two elevator casings and these extend only a short distance above the deck close to the back-head, on each side of the firedoor.

[rtroop]

It’s a coal pusher that was designed to help move the coal forward in the tender.  It was usually a simple steam operated, (not air,) reciprocating piston that could be moved in and out of a cylinder (the part you see). Attached to the piston was a piston rod which connected to one or two pusher bars. The assembly was mounted on the slope sheet of the coal bunker in the tender.  The at-rest position was with the piston extended.  When the piston was retracted it pulled the pusher bar(s) to the rear which loosened the coal.  The piston was then extended which pushed the loosened coal towards the front of the tender.  The operation of the pusher was independent of the operation of a stoker if the locomotive and tender were so equipped.  The primary reason for the pusher was safety.  It kept the coal in reach of the fireman or stoker auger and eliminated the need for the fireman to crawl over the coal pile I to the rear of the bunker to loosen and shovel coal forward.
Here is a link to a patent document that pretty well describes its operation in detail:

http://www.google.com/patents?id=HvdTAAAAEBAJ&pg=PA1&source=gbs_selected_pages&cad=2#v=onepage&q&f=false

The drawing in the patent shows two articulated pusher bars connected to the piston

Here is a link to a photo of the cylinder and single pusher bar inside a British tender:

http://www.flickr.com/photos/johnneave/6283630360/in/photostream/

[Chris333]

BTW Max,

I have a LL 0-8-0 tender shell that has the pusher on it. As a bonus it says Northern Pacific down the side     If you want to trade them out let me know (I did remove the back-up light)

Pics:




You can see where I yanked the light off. 

[mmagliaro]

Thanks for all the info everyone. 
I did keep web searching and did discover what this thing was after all.

It wasn't easy at first because I didn't know what it was called.  But once you started using the term
"coal pusher", I was able to find it.

I was surprised to learn that some of them were air powered and some were steam powered.

Chris.... check your email about that tender shell.  Yep.  I'm interested!

[pnolan48]

Max,

In many industrial applications, steam was used directly when hot, wet exhaust wasn't a problem. If steam exhaust was a problem, then steam was used to power an air compressor. I was puzzled by all the pressure tanks on steam powered ships until an expert ship modeler explained it. The advent of turbines and copious electrical generating power eliminated some of the tanks, and almost all of the high pressure steam fittings for deck equipment. At least that was the explanation of a previous-generation neighbor when I talked to him about his career as a steam fitter.