Patent for "a peculiar construction" (lines 11-12) that will reduce the liability of a trolley running off of the trolley-wire. This construction "involves a trolley-wheel carried on an axis fixed on the trolley pole or harp and an auxiliary wheel yieldingly mounted on the pole and pressed against the under side of the wire, so that should the pole drop slightly the auxiliary wheel will move relatively to the pole and reduce this contact with the wire." (lines 12-19)