As much as I dislike the UP, I went ahead and got the N Scale Sunset Ltd brass 4 car M10000 set. Ugly as sin, but for whatever reason, I like it! Maybe because of its uniqueness. Have not figured that it yet! But, I have a question regarding the train. I know the original was a 3 car train. When was the 4th car added? Or was there ever a 4th car added? Photos I've seen, in one book I have, shows 3 cars. And shows an M10001 with 6 cars. Just wondering if the set I have is accurate for some time frame. And if it is, what time frame does it fit? Any information appreciated. Thanks.