British and American troops were transported to the Western Front in the boxcars marked with "40-8" to denote their capacity: 40 men or 8 horses.

Between 1940 and 1944 occupying German forces used forty-and-eights to transport troops, POWs, horses, freight, and civilian prisoners to concentration camps.

Trains of forty-and-eights were frequent targets of opportunity for Allied fighter-bombers, with carloads of prisoners occasionally being victimized.

As France was liberated forty-and-eights were used to transport Allied soldiers and materials to the shifting front through War's end in 1945.

Called the Merci Train, it was sent in response to the Friendship Train America had created two years earlier to aid France in the dire immediate aftermath of World War II; 700 boxcars worth of donated supplies were collected across the U.S. and shipped across the Atlantic via donated transport.