Pull one card from each and pair them up. Do this ten times and you have your train . No, I don't mean running your train around and around watching the engine chase the caboose. I don't care what the shape of your railroad is, if you turn them on to watch them run and that's all your doing. Operation gives a purpose to your railroad, to your trains, a reason for being so to speak.
Operation means having train deliver loads, pick up empties, deliver loads, return empties.
In other words. Well, sure its all make believe, but it adds so much more to your enjoyment of your trains. Think about it. Then do it. A engine is assigned a train.