After the good experiences with the Deh 4/4I rack and adhesion railcars, the Furka Oberalp Railway received four modernized successors in 1979 which were designated Deh 4/4II. Two more followed in 1984. They had the same bogies as their predecessors, leading to the same power output. But instead of aluminium bodies, they have lightweight steel bodies with corrugated walls.
In service, the Deh 4/4I and the Deh 4/4II are being treated as the same type. Usually, shuttle trains are being formed with a power car, two second-class coaches and a first and-second-class control car. There are also reinforcement sets consisting of a coach and a control car, but they can only be used on inclines of up to 11 percent, while a shuttle train alone can also be used at 17.9 percent.