A press release from Union Pacific Railroad; March 22, 2018:
Since disassembling UP No. 4014, the ‘Big Boy,’ the Union Pacific Steam Team has cleaned, inspected and repaired nearly every part of the locomotive down to its smallest piece.
Now, the UP Steam Team, headed by Ed Dickens, is putting it all back together starting with the boiler’s fire box and combustion chamber.
“Modern American steam locomotives use what is known as a fire tube boiler with a stay bolted firebox,” Dickens said. “As the coal fuel is burned on the grates inside the fire box, the combustion gases flow through the fire tubes to the smoke box in the front of the locomotive. There, the smoke is driven out very rapidly by the exhaust steam pressure from the two engines on the ‘Big Boy’ out of the smoke stack.”
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