The Missouri Pacific Railroad issued the diesel perpetual calendar with The Eagle illustration in 1948. These calendars were given out free to businesses to promote the railroad's freight and passenger service. You are buying only the replacement cards and not the metal calendar.
The Missouri Pacific Historical Society saw a need to reproduce the months and date cardboard cards as many pf the original sets were worn out or lost. If you have a good set of cards you can now put them away and use these on a daily basis.
When we reproduced this set we scanned an original set that was unused. We had two of the original metal silver calendars that had different colors due to aging over the years. Our decision was to match the original cards as closely and disregard the colors of the metal calendars. In 2017 the printing processes are different that in 1948 and silver was no longer available as a background color. We chose the closest color to compliment the old calendars. As you can see in the photo the new cards look great on the old calendar.