During WW2, the People of the US sent boxcars full of goods they donated 1to the people of France as they were under siege. The railroads accomodated this giving by providing specially labeled box cars to carry the goods. After the way, the People of France returned the favor with 48 box cars -- one for each state -- loaded with goods given by grateful families. This was referred to as the Merci Train. Many of these wooden cars survive to this day (I believe the California car is in the State Railway Museum in Sacramento). When I first visited McCormick-Stillman Railroad Park in Scottsdale, I saw the Arizona car on display, protected from the sun and rain in its own shelter). I finally got around to taking a photo. I was thinking that the MTH European box cars would make a nice set of these, but that never happened.
