a prior art electrohydraulic gas exchange valve train for a variable operation of a gas exchange valve 1 that is spring loaded in closing direction the section shows an actuator 702 that is fixed in a hydraulic unit 3 that in its turn is arranged in a cylinder head not shown of an internal combustion engine between a camshaft and the gas exchange valves and serves for a variable lift transmission of a cam lift to the respective gas exchange valve 1 the actuator 702 comprises a hollow cylindrical actuator housing 704 that is fixed through a screw connection 5 in a reception 6 of the hydraulic unit 3 and further comprises a slave piston 7 and a hydraulic valve lash adjuster 708 both of which are received axially movable in the central bore 709 under a choking valve 10 which serves as a hydraulic brake the slave piston 7 which is loaded through hydraulic pressure in its turn actuates a pressure piston 711 of a known type that through a compensating housing 712 which contacts the gas exchange valve 1 forms a variable height pressure chamber 13 of the valve lash adjuster 708 in the operational state illustrated the gas exchange valve 1 is closed and the slave piston 7 and the valve lash adjuster 708 are accordingly fully retracted into the actuator housing 704 in contrast fig7 b shows the actuator 702 in the disassembled state of the.