A single slot valve shaft is in a vacuum body between adjacent vacuum chambers, such as a process module and a transport module. Separate valves are provided on the single shaft actuator for each of two valve body slots, each body slot being closed or opened according to the position of the single shaft. The separate valves allow a vacuum condition to be maintained in the transport module while an adjacent process module is open to the atmosphere for servicing. The single shaft allows access to an open valve for servicing the open valve by way of stops that limit drive travel and hold the valve in an open, but not vertically-spaced, position relative to a respective slot. The open valve is easily reached by a gloved hand of a service worker. The single shaft is mounted on a first cradle, and the first cradle is mounted on a second cradle. Two separate shaft drives move the two cradles to position the single shaft to locate the valves between the slots to open one slot and close the other slot. Another separate shaft drive moves the single shaft vertically down from the open position and away from the slots to expose seal surfaces around the slots for cleaning.