Sentence:  My estimable love and gratitude go out to my family for their continued support and patience in standing by me over the past months while I literally withdrew from life to &#39;grab a tail feather&#39; and fly with this runaway <WSD>freight-train</WSD> of a project. 
Meaning of the word marked with <WSD> tags:  (by extension) A large, unstoppable force; a juggernaut.