Diesel locomotives with hydraulic transmission may be equipped for hydrodynamic braking. Maximum speed was either (depending on the setting of the two speed hydraulic transmission). Power is transferred via a Voith T211RZ hydraulic transmission. Hydraulic transmission for locomotives was developed in Germany. In keeping with their policy, a new locomotive with a hydraulic transmission was envisaged. The experimental H800 model from 1986 featured an articulated chassis and fully hydraulic transmission. Instead some sort of hydraulic transmission was to be used, although not initially specified. Engine speed is constant, with a hydraulic transmission modifying speed. Their early withdrawal was caused, primarily, by BR classifying the hydraulic transmission as non-standard. Because of their Mekydro-design hydraulic transmission units, the locomotives became known as the Hymeks. Most new locomotives use diesel-electric transmission, while older and lighter ones have hydraulic transmission. These drove Brush generators and traction motors, rather than the hydraulic transmission of the "Westerns". The majority of British Rail's second generation passenger DMU stock used hydraulic transmission. The VLocity uses a Voith T312 hydraulic transmission system with dynamic braking capabilities. Both of these used hydraulic transmission and were less bus-like than the Pacers.