Probably my favorite locomotive there: between the sheer enormity and age and weather-derived character, this just has so much presence in person. I really wish there was something next to it to provide a sense of scale, I can't accurately capture it in camera and I don't know how to describe it. If I had to guess it easily topped 16 feet. Think about that the next time you go under an overpass and see a sign that says 14 or 15 feet. Then think of this next to your car.
And yes, there's a Union Pacific 4000 series locomotive here too, so I have a fairly good benchmark for what a "big" locomotive is