Steve: Those are really great tank cars. I am sure you already know but the 2 white tank / maroon car is the almost the most scarce of the 2 tank breed. There is one more , same number5543, Gulf - blue with orange tanks that is quite rare (for Marx). The 3 domes have 2 very rare variants an Exxon made in '74 only and a Milk made in '60 only. Candidly I have seen the Exxon once or twice (too much $$ for me) but have never even seen the Milk. These are all numbered 5553. If you have any of these (and you always seem to have several ) posting pictures of them would be great because even pictures of them are few and far between.
Great Tank Cars, Steve, I admit to being a Tank Fan-a-holic of any brand so I really loved the pictures.
Don