Volvoguy87 Wrote:
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> When I was doing my research & reading prior to
> taking the firemans' school at the C&TS, I learned
> a great deal about coal I didn't know before. A
> significant amount of the energy in coal isn't in
> the solid coke, but in the volatile gasses (eg.
> methane) also contained within the coal. Over
> time, the volatile gasses can dissipate. The coal
> looks the same, but it won't burn as we're
> accustomed to, or how the firebox was designed to
> burn it.
>
> I experienced an example of this when firing down
> the 4% and coming into Chama. As you might
> imagine, the trip down the hill uses very little
> coal, so by the time we got to the 1st crossing,
> the volatile gasses were spent, and I had a layer
> of coke burning quietly on the grates. As the
> engineer opened the throttle as we got closer to
> the yard, the draft did not wake up the fire. The
> fire was about as thick as I wanted it to be, but
> the instructor told me to toss in a scoop or two
> and see what happened. The fresh coal really
> livened things up! Those few scoops brought the
> fire back to life, and we completed our switching
> with a few more scoops as instructed and a nice
> bright and lively fire that kept the pressure
> gauge where it needed to be and the engineer
> happy.
>
> I couldn't imagine trying to run a locomotive with
> a fire of dead coal. Thick fire on the grates, no
> gasses burning above the fire, and nothing I do
> can make it work properly!
>
> Dave
What you are describing is also what a fire of anthracite looks like. I used that for a while in my model locomotive. It kept the engine hot when just sitting at the station, but could not generate enough heat on the road.
What you are also describing is a thick ash bed, at the end of the day. An end of day fire, with a thick layer of ash, can look like a big fire, when in reality only the top few inches is actually burning.
