premise: A mechanical failure struck Hong Kong's landmark Peak Tram during rush tourist hours Saturday, bringing the service to suspension and upsetting hundreds of travelers.
  The accident occurred about 10:00 a.m. (0200 GMT) Saturday when about 100 tourists rode the centenarian tram from the mid-levels in Central District to the 500-meter height Victoria Peak.
  The trapped tourists had to walk from the mountainside to the tram's starting terminal after it failed to restart. No one was hurt.
  It took engineers six hours to fix the tram system and the Peak Tram company resumed service at about 4:20 p.m. (0820 GMT).
   What was responsible for bringing Hong Kong's landmark peak tram to a suspension?
hypothesis: The accident occurred about 10:00 a.m