Can you tell me about trains?

I currently reside in Bowling Green, KY and I want to know more about trains. Correction, my three year old son, who is obsessed with trains, wants to know more. We have two tracks running behind our home. There is no rail yard in town, yet the trains are often parked overnight on the tracks. Sometimes the train flies through really fast and other times it barely moves. Sometimes two trains will be going really fast in the opposite direction while other times, one train will be stopped and another flies by. The nearest yards would be Louisville (2 hours away) and Nashville (90 minutes away). We do have a historical train museum in town, but they don't know anything current. I'm just looking for more information for my son. Please speak non train lingo as I'm clearly ignorant in the train department. Any help would be greatly appreciated as the, "I don't know" answers are received as Mommy is just withholding information! Thank you!