Steam Locomotive Firebox Explosion on the Gettysburg Railroad ...

According to the regulations, the boiler
must be washed once a month and the
spindles must be reamed. When asked if the
amount of scale found in the spindles could
have accumulated between monthly
cleanings, one steam-locomotive expert said,
“No, no possible way.” Another said, “I
have never seen a locomotive that had as
much scale inside the water-glass spindle as
the 1278. I worked on a lot of locomotives
all over the country and never saw anything
like this.” The chief mechanical officer
(CMO) of the Strasburg Railroad speculated
that in such a restricted condition, the
spindles would be much more susceptible to
being blocked by floating material or scale
flake. The investigators were unanimous in
their conviction that the amount of scale
found in the spindles could not possibly
have accumulated within the relatively short
time between monthly boiler washings,
Figure 12. End view of plugged spindle.
regardless of the condition of the water used.
(See figure 13.)
The water glass itself was a glass tube
about 12 inches long and 1/2 inch in diameter.
Running the length of the glass was
a 1/4-inch-wide faded red background line
that was barely visible. The diameter of the
bore (about 1/8 inch) appeared smaller than
the 3/8-inch bore with which the inspectors
were more familiar. They considered
whether a smaller bore would be more
susceptible to some form of capillary action
or to being plugged by lose scale (either of
which could yield a false reading). However,
after they examined and tested the glass,
they decided the diameter of the bore was
acceptable. (See figure 14.)
Safety Board investigators used a flexible
clear plastic hose to measure the response of
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