I just picked up a new to me copy of Lionel's 2019 Volume 2 Catalog at the local hobby shop. I found their page on Disconnet Passenger Cars that are Scale cars, only 3 1/2 inches long each.
Lionel does call these cars "Whimsical"
But they do want $44.99 for each car. I know these cars are in a catalog and but I see some for sale.
I do sometimes run a Lionel Rock Island Bobber caboose on my General trains and am building a second one from a cut down Lionel SP caboose so the baby cars may not be that unusual.