Safe commercial ziplines typically use passive zipline brakes; the rider doesn’t have to intervene in the braking process. Active zipline brakes however, imply that rider has to be active in the braking process such as dragging a gloved hand on the cable.
Passive zipline brakes are:
Gravity: Cable has a sag that slows down the rider at the end of the run. Good for short zipline with use of an active brake
Springs: A series of springs and spacers are placed on the line to more or less gently stop rider. Heaviest rider have a smoother stop.
Magnetic: The magnetic technology is based on Eddy Current; a reaction between magnets and a non-conductive metal such as aluminum. It provides excellent braking but is quite expensive. Most riders will stop pretty smoothly.
Progressive: Perfect for the highest landing speed ranges over 90 km/h. Extremely easy to adjust and every riders will have a smooth stop evenly when braking distance is adequate.
Your choice of zipline brake design depends on many factors: expected landing speed, available braking and buffer zone lengths, type of trolley and budget.
We can usually plan for a zipline brake design at the earliest stage of consulting but it is only after we visit the site and discuss the different options with the client that we can confirm the design and start planning for it.