A method and an apparatus for supporting time shift playback in an adaptive HTTP streaming transmission solution are disclosed. A function carrier located at or near the front end of each drawer rail has one or more function elements for taking up, holding andor connecting parts of the drawer andor one or more function elements for readying, supporting andor completing drawer functions. The value input to each of the FF circuits is determined by logical operation of at most two logical values, so that the counter circuit can be adapted to the increasing frequency of a clock signal CLK. The Track Interface Unit converts the commands to modulated signals in the form of data bit sequences which are sent down the track rails.