I am selling some N Scale for a friend who passed away. Money is going to his widow. He had a lot of old N Scale. there are some Kadee and Micro Trains cars from the early years. As I was researching some of the cars on E bay, I ran into a seller that sells at collectable prices (or tries to). They mentioned Kadee ribbed back wheels being included. I looked at the cars I had, and none of them had ribbed back wheels. When did Kadee include Ribbed back wheels in N Scale? Did all Kadee come with ribbed back wheels? What about early Micro Trains, did they have ribbed back wheels? When did MT change to flat back wheels? Thanks in advance for any help.