What Does Your Heart Say?

I took Ian to the doctor this morning because since Saturday he has had a fever of 101 to 103.5. While we were waiting for the doctor to come in I told him what the doctor would do when he came in. I told him that he would check his ears, look in his mouth, look in his ears, and probably listen to his heart. I then told him that our hearts sound like....ba bum ba bum ba bum.  He looked at me a little confused and said that his heart doesn't say that. Curious as to what he would say I asked him "Well what does your heart say then?" He very quickly replied "It says chugga chugga choochoo". Even though Ian is sick he can still make his mom laugh.