Challenger

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Challenger? More like Big Boy!

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Challenger is the little distant cousin and predecessor of Big Boy. He is a 4-6-6-4 articulated steam locomotive and has 104 brothers and first cousins (total 105) representing 5 classes. The Union Pacific Railroad thought it would be helpful to build a new locomotive that could carry heavy loads of freight up the mountains at high speeds, so they created Challenger to take the challenge.