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Rules and specifications for the Trolley competition


The objective of this competition is to see who can design and construct the motorized trolley that will travel along a zipline cable the fastest (in the shortest time).


Only one trolley may be entered per 2-student team. Read the specifications carefully. Any trolley that does not meet these specifications will not qualify for the competition.


  • The cable is the only material that will be furnished by the host. All other materials must be supplied by the competitors.
  • The cable (furnished by host) will be a level horizontal run of approximately 50 feet length. The cable size/type is similar to the one at this Amazon link.
  • Trolley motors and power supplies (furnished by competitors) must be uniform for all.
    • Motors shall be DC 1.5-3V 24000 RPM hobby motors.  Power supplies shall be two standard AA batteries.  One motor per trolley.
    • Please see this Amazon linkfor suggested kit.  This kit is not required, but motors and battery compartments must be the type in this kit. 
  • All other materials and trolley configurations are to be determined by the competitors.


  • With the exceptions of the motor and power supply detailed in part 3, any construction materials or methods for the rest of the trolley are acceptable.
  • The maximum permissible trolley weight is 2.0 lb.
  • Trolleys must be able to be placed on the pre-strung cable without detachment of the cable or further assembly or the trolley. That is, there can be no detaching of the cable from its support and threading it through trolley wheels, and there can be no fastening of trolley appurtenances after it is placed on the cable.
  • The trolley must fit within a 36”x36” square prismatic envelope centered on the cable. It can suspend above, below, or alongside the cable, or any combination of these, but it must fit within the 36”x36” prismatic envelope centered on the cable. See Figure 3.

See Figure 3. 

Trolley design sketch


  • The trolley will be placed on the cable.
  • One student will connect the power supply and let the trolley go.
  • The other student will catch the trolley on the other end (so as not to crash into the support). Judges will record the travel time.
  • Two test runs will be performed. The average time of the two runs will be used.
  • Repairs to trolleys between runs will be permitted. “Repairs” means minimal work to restore the trolley to the original condition (duct-taping, tightening loose pieces, etc). Trolley modifications or improvements between runs is not permitted.
  • The trolley with the fastest average travel time will win.


Trolleys will be checked for compliance to these specifications prior to testing. Trolleys with the wrong motors, power supplies, or over the size or weight limits will be disqualified.

For questions about these specifications:

Damon Feuerborn 
(913) 469-8500 ext 4909

Matt Andring
(913) 469-8500 ext 3901