consist of the compressor and the components necessary for their operation.

The motor M, usually an electric motor , is connected to the compressor CP via the clutch CL. Compressor and motor are the compression unit, installed on a common foundation F. In a machine dynamic sense, that is in relation to variations in  compressor speed, foundation stresses and vibrations , the compressor station has to be considered as a unit.

In a thermodynamic sense all working chambers WC of all stages , together with the corresponding  interstage systems IS form a unit.

Besides the cooler CO and the connecting pipes CP  the pulsation dampeners  PD on both sides of the working chambers (to reduce gas pulsations) , also the droplet separators DS to remove condensated humidity and entrained lubricating oil  belong to the interstage system .

Normally a compressor station  is fitted with a cooling water system CWS for the working chambers and for interstage cooling, also an oil system  OS for the lubrication of the crank drive and the cylinders.

The control system CS  regulates the start up and shut down procedures and controls the compressor according to changing working conditions. It also monitors the compressor station in order to avoid damage and to initiate repairs in dependence of the condition of its components.