I have looked at the internet for the blunt end dome observation car, and the only one I could find was made of stainless steel and they are asking nearly $700 for it! I do have one in plastic which I use on my post-1956 Denver Zephyr. I don't recall where I got it, nor the brand. The only indication of the source is "Made in Italy" on the underside. As a suggestion, if you don't mind modelling the 1935-1955 version of the Denver Zephyr, you can just use a round-end dome observation with coriggated sides. There are a number of those available in Burlington livery.I believe that was the last full set of passenger equipment purchased in the US until Amtrak's Superliners decades later. The hard part will be the square end dome observation car. It has never been done in plastic, and rare even in brass. Some company make an "end piece" where one could cut the short end off a Con-Cor dome car and fit this piece into it, but I would think those are hard to find these days too.