I lived with an active train track literally in my back yard, so I grew up loving them and walking miles down the tracks with friends. There was a criss-cross a few blocks down, and that track frequently carried long coal trains. I'd bicycle down to watch them take minutes to go by. I still enjoy catching a train going by. I wasn't ever much into the engines or particular models. The ones near me were always big diesel engines, Union Pacific (yellow/gray) and MKT (green) I believe, so I enjoy seeing those patterns. For me there's something about the rails going seemingly endlessly, with much less imposition on the landscape than a road. I especially like rails where the ties are hidden, and you just see rails peeking up above the grass/dirt/pavement. There's also something about the massive scale they move things on, being so heavy and lengthy yet rolling seemingly smoothly by without any problems.