As a verb "tump" and "tump over" are onamonapidic. Southern US usage would never say, as one online dictionary uses as example, "tump over a glass of beer." Beer glasses do not make a "tump" sound. A bucket of nails might tump over, a cardboard box of clothing might tump over, but a telephone pole, a beer glass and a piece of sheet-metal would never be able to tump over.
Also, as a southerner, I believe that anything which tumps over does so from a short distance-- as in only short items tump. —This comment was unsigned.