Reportedly, the geared steam turbine used excessive steam because there was not a very good way to get "cutoff" as with a locomotive with a valve gear. Especially at slow speeds too much steam was needed just to keep moving. Remember, steam in a locomotive with cylinders exerts power by expansion against the resistance of a piston, and the flow of fresh steam into the cylinder can be reduced and the expansion of the reduced steam still occurs. With a turbine the steam has to exert continuous pressure against the turbine blades, so there isn't the same opportunity for expansion to occur if the flow is reduced.
The PRR's only four-cylinder articulateds were a few 0-8-8-0 yard switchers, if I recall correctly. The duplexes (S-1 6-4-4-6, T-1 4-4-4-4, Q-1 4-6-4-4, Q-2 4-4-6-4) were rigid-frame, not articulated. They had their problems but certainly used steam more efficiently than the turbine.
Dr. R. C. Leonard, "Richard Leonard's Rail Archive" ( http://www.railarchive.net/