I took this image of Union Pacific Big Boy 4014 in Salina, Kansas where it was overnighting after coming through my town. The locomotive is so large and I was very close to it that I actually did a 4 image panoramic to get it all in, top to bottom and lengthwise. The Big Boy got it's name from something that has been recreated on this locomotive and can be seen a bit in this image. When the first one of this style locomotive was produced, number 4000, a worker chalked the words "Big Boy onto the smoke box door as is seen here and the name stuck for these as they are certainly big. Their wheel arrangement is a 4-8-8-4 articulated style meaning it can move in the middle and navigate tighter curves.