The OLE system has to adapt to the sinuous lines in the mountains

Fixed Catenary OLE - vertical or inclined

Right from the pioneering stage of railway construction, Switzerland's topographical conditions have determined the lay of the line. Even to this day, narrow radii decide the speed at which a line may be travelled and maximums of 80 to 100 kmph are the rule in some cases. For reasons of economy, semi-tensioned contact line systems were chosen when electrifying these lines and have stood the test of time to the present day.