North Platte is where I was born (but not raised) and my family always said (when I was only 2 years old) I would be saying, "choo, choo" when a train couldn't even be heard...lo and behold about 10 minutes later a train would go by our house. Funny how the train thing came out in force at the age of 42!
Boy Al, it sounds like you ripped a page right out of my families book. When I was 11, my family took a 5 week cross country trip via car. Among other things, we drove from Sault Ste. Marie west on the Trans Canadian Highway to Vancouver. This highway parallels one of the Canadian RR's major lines for much of that distance.
My then 2-year-old brother learned his first two words on that trip, Cow and Train. And much like you, he'd be sitting in his car seat and would start yelling train, train! The rest of us were looking around and saying, where? Sure enough, 5 to 10 minutes later, here would come a train into sight. We never did figure out how he was seeing things that we weren't. About the only thing we could think of was the added hight of the car seat.