MoPac Mechanical Department Card showing the paint codes used on the original Eagle and later changes.

First generation Eagle Colors

In 1939 the EMD E-3's were delivered from EMD

Second generation Eagle colors

Introduction of Jenks Blue

On page 73 of Kevin EuDaly's book on 'Missouri Pacific Diesel Power' there's a shot of 4169.  Caption reads GP7 4169 has the unfortunate distinction of being the first unit to be painted in Jenks Blue.  The date on the photo is June 21, 1961.  

Eagle Cab Decals Introduced

As to the small Eagle on the side of the cabs, I was working in St. Joe in 1974 and remember two brand new  MP1500's being assigned there and they were the first I saw with this new paint scheme.