The great thing about toddlers is that they don't have the same filters as the rest of us. So while we're all seeing a train coming and saying—in our heads—"Train! Train!" and then "Aaaaaaaaah!" as the train goes by, and then "Bye bye!" when the train is gone, they're the ones actually yelling those things out loud.

Keep on yelling at trains for as long as you can, little guy.

Sources: Tastefully Offensive