Re: Faux firebox (now firebox Facts!)

[Royce Woodbury]

Hi Keith.  Thanks for the info.  It always amazes me how much knowledge 
is in this group.  And how much skill it takes to actually drive a steam 
locomotive.  Don't imagine there's alot of "kick back" time like I'm 
sure there is driving a diesel.  They took all the fun out of it !

royce in SB
Keith Taylor wrote:
Hello Royce.
You wrote:
 

My supposition is that you should see the bottom of the
firebox down to the mudring and then "something" related to the fire -
maybe called the "ashpan" ?  The photos that I've seen seem to have
"doors" on them controlled by a rod.  This is the part I don't
understand.
   

The "doors" you mention are located at the front and rear of the ash
pan, and are called "dampers" and they control where the air enters the
fire, and how much. When you are running forward, with a coal fired
locomotive, you want the bulk of the air entering the fire to come from
the rear, as air entering from the front will just take the shortest
path up along the front seet of the firebox, and enter the tubes without
having supplied oxygen to the coal! And, it has the specific bad effect
of chilling the sheet nearest the front and breaking stay bolts and
loosening tubes. So, for forward running, you mostly close the front
damper, open the rear ones, and force any air entering to come up
through the firebed! The farther you open the damper, the higher the
amount of air, and hence a higher firing rate! So, lugging a drag of
felled trees up a grade, the damper would be wide open. Loafing along
drifting, you can close it down and save coal, since you aren't working
the boiler very hard. These dampers (the doors) are controlled by rods
that extend up in the cab floor, where thefireman can control the
opening by lifting the lever and hooking it by a notch in the lever, to
the cab floor holding it at whatever position he wants. The door on the
side of the ash pan, as shown in Vance's photo, is the clean out, where
ash accumulations are removed. If you let the ask get too high, it does
two things, once chokes off air supply to the grates, and in some cases
where the ash was allowed to actually reach the grates, it kept air from
hitting the gratesm and cooling them. With the ash acting as an
insulant, the grates can reach the temperature where they will actually
melt!
So, now you know what the "doors" are, they are firing controls on wood
and coal burning locomotives.
Keith    In frosty, and still snow covered Maine!