USRA-style 40' autobox

{ppcode} When were those retired?

I merely found the picture. Maybe a Wabash guru could answer your question. I looked up Wabash in my April 1954 Official Railway Equipment Register. It lists Wabash series #40000-40999 as an XM (ordinary box) with steel underbody, single-sheathed, composite construction. Internal length . 40’6” Exernal length Extreme width 10’ Extreme height 14’9” Door opening 11’ capacity 40 tons.
The car is marked “Automobile” in paint almost faded away in this 1943 photo, but not classed autobox in 1954.