Generally 2-8-2s were for freight and 4-6-2s for passenger, but there certainly are examples the other way around. New York Central had 4-6-2s that were primarily built to be freight engines. Canadian National had 2-8-2s that were primarily used on passenger runs between Port Arthur / Fort William Ontario (today's Thunder Bay) and Winnipeg Manitoba.
As noted, as diesel passenger engines bumped steam out of that service, it was not that unusual to find a Pacific (or even an NYC Hudson) on a freight train.
