You watch a movie about RR crossing safety in Driver's ed, but you only pay attention to the trains and not the cars.
I know I did! And it's not like I didn't already know that stuff anyway...
Someone talks about something, and you can relate it to trains.
You are in school and you're bored in English class as your teacher lectures you for 40 minutes on the proper use of commas, and all you can think about is trains.
In Spanish class, you get excited because Chapter 1 is about trains (el tren).
You have to go somewhere, and you ask your parents if you can take the train.
You take the train to school, even though you can take the bus for free (I wish I did, but I can't drive yet, and my mom wouldn't get me to the station in time).