My experience clerking at the NPTCo in Portland in 1961-62 with NP and GN covered hoppers was that a small group was dedicated to bulk feed service from the large Albers mill across from Union Station. There was nothing in the car lists or documentation I typically saw, but the same cars kept showing up for another outbound load. These covered hoppers were build within the time-frame of this list. Boxcars in bulk feed service (as opposed to bagged feed service) were also dedicated, and were so designated in track and industry switch lists with "FEED". Ditto for hide cars which were marked "HIDES" on their switch list entries. If you ever walked by either kind of car in a yard, you would know why unless you had a bad head cold. :-)
