During "Desert Storm" Wisconsin Central put these flags on the side of the cab of many of their locomotives (see picture below). Then after 9/11/01, they got out any extra flags that they had left over and applied them to as many WC road locomotives as possible. Most of them have the blue field facing the front of the locomotive, but as they started to run out, some of them (like #2500, below) ended up with the flags the same on both sides (one facing front, the other facing back).
