I can't say thanks enough for posting these fantastic images of 1950s era passenger railroading MrFSS! Cincinnati Union Station was and remains a beautiful facility. But for those of us who are too young to have seen it when a few dozen trains a day from multiple roads operated through the old train sheds, this is particularly outstanding. My brief touches over 15 years ago with the last remnants of the L&N - by this time faded gray and yellow Geeps waiting for a trip through the CSX paint shop - make me forget that earlier L&N schemes were rather colorful, and that red nose logo was something!
I absolutely love the comparative Observation "architecture" shots between those two B&O trains. Note how the Cincinnatian consist is obviously streamlined heavyweight equipment with the high roof profile. I believe this was the daily train up to Detroit and return, along with the Ambassador. Despite its slowly dwindling coffers, the B&O ran a good looking line of passenger trains.
I knew the X train was yellow, but I thought it was yellow and black, not dark green. You can see the obvious Baldwin styling in the cab....which was nearly identical to the cab design used on the Sharks. Look at the length of that front truck in the broadside shot Cavalier linked! Wow!