This site describes FastPass tickets used at disneyland with many frequently asked questions
 
http://www.mouseplanet.com/al/docs/fast.htm
 
and
 
a Google search  for     "timed tickets"  
will result in many hits for many institutions using this device
Washington Monument
Lewis and Clark
and many other non-profit museums etc.
 
I am sure that direct contact with them would provide good infomation.
 
Barbara Hass, retired librarian
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