The Brig-Visp-Zermatt-Bahn ABDeh 6/6, later known as the BDeh 6/6, and later still as the Matterhorn Gotthard Bahn BDeh 6/6, was a two member class of metre gauge, rack rail, electric multiple units operated by the Brig-Visp-Zermatt-Bahn (BVZ), and later by the Matterhorn Gotthard Bahn (MGB), in the Canton of Valais, Switzerland. The later classification of this class, BDeh 6/6, signifies a vehicle with no first class facilities, but otherwise the same characteristics as a vehicle of the original classification.