By 1968, the railroads operating the California Zephyr had changed the Vista-Dome Views booklet into a brochure. This might have made it less expensive to print, but it probably made it harder to use as it unfolded to an unwieldy 16″x18″.
The text hasn’t changed much. The photography guide in the 1955 booklet, however, was replaced by a timetable, which is handy in a way and probably should have been included in earlier editions to save the cost of printing separate timetables. Printing brown ink on lighter-brown paper, however, is always a bad idea.