Uninterestingly, there are two directions that the
Skytrain can move in: forward, and backward. However, in terms of
Skytrain control definitions, these are refered to as the "one direction" and the "zero direction" respectively. This might be due to the nature of the
linear induction motor which doesn't differenciate between 'forward' and 'backward' per se, but only positive and negative polarization. Also, all
Skytrain cars have no 'front' nor 'back', which makes the traditional forward and backward definitions meaningless.
The 'one and zero' definition is also used to identify sections of Skytrain stations. For example, the "one side of Main inbound" refers to the section of Main Street Station that exits onto Terminal Avenue. Whereas the "zero side of Joyce outbound" refers to the side of Joyce Station that exits onto the west side of Joyce Avenue.
Since this is a node about Skytrain motion, I might as well mention that all trains have two modes known as 'auto' and 'manual'. Normally, all trains are in 'auto' and follow a pre-programmed Skytrain route that increases and decreases speed slowly for a smooth ride. However, occasionally it is necessary to drive a train manually -- and the drivers are not as nearly as smooth as the computer is.
In order for a train to be placed in manual mode, a strict Skytrain protocol must be followed:
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First, a request is made to Skytrain control. Control then will agree or disagree with the request to put a certain train in manual. This stage can be called 'pre-authorization'.
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The requested train is then put on a Skytrain hold by Control at the station requested.
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The staff member who will be piloting the train then occupies the control seat in either the zero or one end of the train, and begins to unlock the various train controls for use.
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The staff member then radios in with a formal request to put the train in manual. The request consists of the intended travel path (usually noted in track sections or station-to-station notation), direction of travel (zero or one direction), and personal code identification.
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Control radios back, repeating all of the above information, plus a military-style time stamp. This unlocks the train from auto and places it in manual.
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Staff member radios Control with the time stamp (confirming repeat), finalizing the procedure, and begins to move the train in the desired direction.
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Skytrain Control confirms that the train is moving in the desired direction, and broadcasts it. (i.e. "Zero direction confirmed")
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After the train reaches its desired destination, the employee locks up the control cabinet and radios in for a request to return a train to 'auto' mode.
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Control acknowledges the request by broadcasting the current time, military-style, which is then repeated by the staff member.