Steam Locomotive Firebox Explosion on the Gettysburg Railroad ...

water glass had to be completely
open. Partially opened valves resulted
in the water glass showing a
water level that was higher than the
actual water level in the boiler. The
crownsheets became overheated,
and explosions occurred. Those
locomotives, like the accident
locomotive, had one water glass
and one set of gage cocks.
Boiler- Water Supply System-The
investigators also examined the
devices used to supply water to the
boiler. Two types of water-supply
s ystems are used on steam
locomotives: the injector system
and the feed-water system. Most
steam locomotives have both systems,
but older steam locomotives
may have two injector systems instead.
<strong>Locomotive</strong> 1278 had both
systems. The injector and feedwater
systems can be used
separately or together and can act
as backups for each other; however,
the injector system functions
more efficiently when the locomotive
is standing, while the feedwater
system functions more efficiently
when the locomotive is
valves at the top or bottom of the water glass
are not completely open, the result again
may be a falsely high water-level indication.
According to a leading mechanical engineer
and recognized boiler expert with ABB
Combustion Engineering, several crownsheet
failures occurred in England during
World War II because the water-glass spindle
valves were only partially open. The
English crews of U.S. Army 2-8-O locomotives
were unaware that the top valve of the
The boiler-water supply system consists
of (in order of flow) treated or untreated
water from the tender, strainers in the tender
and delivery hose, the feed-water heater (if
the locomotive has one), the feed pump or
the injector(s) with their respective check
valves to prevent pressure backup, and two
stop valves to shut off leaking check valves.
The injector pumps unheated water
directly from the tender into the boiler,
heating it in the process. The feed pump
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