A magnetic tape drive unit for storage of digital data is disclosed which features vertically disposed supply and take-up reels, double long folded over buffer columns to permit rapid acceleration of the part of the tape in the vicinity of the magnetic head, and dual isolation pockets for additional motion control of the tape. In a preferred embodiment, the inner surfaces of the tape path are lined with glass beaded adhesive tape to prevent friction; fence posts may also be provided to prevent planar contact between the magnetic tape and the walls of the unit. A vacuum capstan is desirably used. In this way, high acceleration and tape speeds are made possible in a tape transport capable of being mounted in the industry standard 19 inch wide mounting rack.