This is an example of a consulting situation I would have never
predicted for myself. Several years ago, I received a call from a
man who needed immediate help. He owned the Sky-Ride cable car at
the Minnesota State Fairgrounds and he was preparing for the State
Fair. He had been experiencing some problems with the ride's
automatic shutoff, and wanted some engineering help to track down
the problem. I visited the site and found the problem was caused by
corroded safety switches on the support towers. These switches,
really forked metal bars, break if a cable car derails, and when the
safety switch breaks (opens the control circuit), the ride
immediately stops. These switches had not been replaced for quite
awhile and they had corroded to the point that some of them cracked.
Occasionally, these cracks would open and trip the safety stop in
the system. Of course, these failures did not compromise the safety
of the system, but random stops were irritating. The problem was
easily fixed; I recommended that my client inspect all the tower
switches and replace those that appeared corroded.
On another occasion, I designed new controls and circuits in the
system in order to satisfy the specifications of a new safety
underwriter.
