Seaboard Airlines #544 is a coal
burning steam locomotive. Coal was the fuel
of choice for most railroads in the
eastern part of the United States.  So how
does coal make this locomotive move? It
begins in the firebox.  The firebox has a
few different layers. On the inside, you've got the burning coal, burning at 2,000
degrees Fahrenheit. Surrounding that, on
all sides except the bottom, you have a
layer of boiling water. Then, on the outside, you've got this steel.  The fire, by itself,
doesn't make the train move. Its only job
is to turn this water into steam as
quickly as possible.  
That steam builds up in the boiler.  You
can think of that like if you blow up a
balloon full of air.  Now I have to hold
onto this balloon, because if I let go,
the air inside the balloon will escape. The
steam this boiler also wants to escape.
It's pressurized to about 200 pounds per
square inch. It wants to get out, and
we're gonna let it, but we're gonna make
it do some work first.  When I want to move the train, I'll pull the throttle, in the
cab. That lets steam flow down a pipe
into these cylinders. Inside this cylinder is
a piston, about that big around, and that
thick.  That steam comes down and it
pushes that piston all the way to the
other end of the cylinder. Then it
escapes out of the hole and out the stack. And the escaping of the steam out of the
stack makes that characteristic "chug"
sound we know and love so much about
steam locomotives. That steam is gone.  But more steam is going to come from the
boiler and push the other side of the
piston back the way it came, and again
escape out the stack.  So, you've got this
piston on this side, moving back and forth
like this. You've got another one on the
other side, working kind of like this.
These are connected to all these rods
and cranks on the wheels and these work
a lot like pedaling a bicycle.
In a typical day, a steam locomotive
might run up to 150 miles and burn 10
tons of coal and turn 20,000
gallons of water into steam. All that
water and coal come from the tender,
right behind the locomotive, where I'm
standing. This tender holds about 10 tons
of coal, enough for a full day's worth of
work, but, only about 6000 gallons
of water. As often as every 30 miles
you'd have to stop by one of those big
wooden water tanks you see in old
westerns, open up this hatch on top of
the tender, pull down the spout, and fill
it back up.  There's a crew of two people
who work up here - the engineer and the
fireman. Now, the fireman, their most
obvious job was shoveling the coal. To
shovel coal, I'm going to grab my shovel off this hook, lean back on this post so
I don't fall over from the engine's
rocking back and forth down the tracks,
step on this pedal, which opens up the
firebox doors, and then I throw the coal
into the firebox. I'll typically shovel
about two scoops at a time, and then wait
20 seconds, and then shovel two more, and wait 20 seconds, and shovel two more,
and repeat that through the course of the
day. The coal inside the firebox is
supposed to be a thin even layer. You
don't want any holes. You don't want any
piles. So I have to be distributing this
coal, mostly by memory, to keep a nice
thin layer of coal in the firebox.
Shoveling coal is the most visible part
of the fireman's job, but the most
important part is actually keeping the
water level in the right part of the
boiler.  This sight glass should have a
glass tube that would fill up with water
and show me the water level. Too much
water, and I'll get water into the cylinders
which can do a lot of damage to a
locomotive, and too little water will
cause the top of the firebox to overheat
and melt, causing a boiler explosion
which launches everything above the
wheels up to a mile away. That will be
bad for me.  I also have to keep enough
pressure in the boiler to give the
engine that power it needs. Pumping cold
water in the boiler lowers the pressure.
Shoveling coal into the fire increases
the pressure. So I'm balancing coal, water,
and how much steam the engineer is using to keep a consistent pressure and a
consistent water level in the boiler.
The engineer has three levers to drive
the train.  The Johnson bar controls if
we're going forwards or backwards and
whether we have more high speed power or
low speed torque.  The throttle puts
steam into the cylinders to make the
train move.  And the air brake lets the
train slow down or stop.
It took the simplest things through this 86 ton machine down the rails: just coal
water, a roaring fire, and a lot of sweat
