Union Pacific steam locomotive No. 4014, the Big Boy, is in one piece again nearly two years after the behemoth was disassembled to begin its restoration.
The Union Pacific Steam Team recently hoisted the Big Boy’s more than 250-ton boiler and rear engine into the air with two massive cranes and reconnected it to its front engine. Getting to that connection moment was a complicated endeavor.
Articulated steam locomotives have two sets of drivers – or complete engine units – with eight wheel sets total. The front set of driving wheels, referred to as the front engine, can move independently from the locomotive's permanently attached boiler and rear engine. This allows the locomotive to better negotiate curves.
Big Boys are referred to as simple articulated locomotives because the live steam is used only once before it’s exhausted out the stack. This type of locomotive creates a very characteristic sound because the two engines work independently from each other and exhaust steam independently, creating a unique “chuff” cadence.
Continue Reading (includes January 2019 Video Update.)