The Auto Braking Trolley or Richardson Safety Trolley (RST) history starting in 2001 when we (AA Machining & Welding, Inc.) designed and manufactured a 60-mph RST-02 for the 2002 giant zipline at Park City Mountain Resort (PCMR); the 3,500-foot-long zipline broke records with a 600-foot drop between platforms. Since then,  dozens of ski resort ziplines have utilized RSTs; our RSTs have an unblemished safety record.

2023 RST Testing is simple and easy to understand. This 20-degree zipline slope established pin or carabiner settings (e.g., 6, 7, 8) for different temperatures NOT the weight of zipliners.