et was
removed in May 1963. The size and shape of the hole, which the plate
covers, indicate that a steam dome or manhole was located at this point.
It is possible that this was the original location of the steam dome
since many builders in the early 1850's preferred to mount the dome
forward of the firebox. This was done in the belief that there was less
danger of priming because the water was less agitated forward of the
firebox.

The firebox is as narrow as the boiler shell and fits easily between the
frame. It is a deep and narrow box, measuring 27 inches by 28 inches by
about 40 inches deep, and is well suited to burning wood. A deep firebox
was necessary because a wide, shallow box suitable for coal burning,
allowed the fuel to burn so quickly it was difficult to fire the engine
effectively. With the deep, narrow firebox, wood was filled up to the
level of the fire door. In this way, the fire did not burn so furiously
and did not keep ahead of the fireman; at the same time, since it burned
so freely, a good fire was always on hand. The _Pioneer_ burned oak and
hickory.[14] For the firebox 5/16-inch thick sheet was used, for heavier
sheet would have blistered and flaked off because of the intense heat of
the fire and the fibrous quality of wrought-iron sheet of the period.
Sheet iron was fabricated from many small strips of iron rolled together
while hot. These strips were ideally welded into a homogeneous sheet,
but in practice it was found the thicker the sheet the less sure the
weld.

The fire grates are cast iron and set just a few inches above the bottom
of the water space so that the water below the grates remains less
turbulent and mud or other impurities in the water settle here. Four
bronze mud plugs and a blowoff cock are fitted to the base of the
firebox so that the sediment thus collected can be removed (figs. 17,
18).

The front of the boiler is attached to the frame by the smokebox, which
is a cylinder, bolted on a light, cast-iron saddle (not part of the
cylinder castings nor attached to them, but bolted directly to the top
rail of the frame; it may be a hastily made repair put on at the shops
of the C.V.R.R.). The rear of the boiler is attached to the frame by two
large cast-iron brackets, one on each side of the firebox (fig. 18).
These are bolted to the top rail of the frame but the holes in the
brackets are undoubtedly slotted, so that they may slide since the
boiler will expand about 1/4 inc