I've always liked the B&O and especially the Lionel PW No 2368 which I only recently (past 5 years) discovered is not prototypical.
Have assembled a few B&O diesels in the blue/yellow/'other' scheme and am curious what is correct.
Here are the Lionel Sharks (rear), a MTH Premier FA B unit and a Williams FA A unit.
Considering my toy train roots, I like the MTH unit followed by the Lionel Sharks. The Williams A unit appears too 'dull' and 'drab' for me at this point. While the other two are lighter they are also not gray - more a very pale blue (especially the MTH) while the Williams is definitely gray. Big difference in the graphics as well.
This is a combination of natural light and an incandescent lamp.
Your thoughts please
PS - Was there a prototype for the MTH ABA set with the light 'blue' pilot, fuel tanks, and trucks?