Elevator cars switch hoistways while traveling vertically

An elevator system for providing service between vertically remote landings of a building, comprising:

• a plurality of vertically and horizontally adjacent hoistways disposed between said landings, each of said hoistways including a car coupler roped through a sheave to a counterweight, each for moving a car coupled thereto up and down in the corresponding hoistway, first coupled to a car heading up, and then coupled to a car heading down, to advance successive cars coupled thereto in alternate up and down directions in synchronism with the movement of cars coupled to the coupler in adjacent hoistways;
• motive means for driving said couplers and said counterweights;
• at least one transition section disposed between a pair of said hoistways, for providing vertical motion control to each of said cars to move said cars between the upper end of the lower hoistway and the lower end of the upper hoistway;
• and
• two pairs of guide rails, each pair extending between said landings, one of said pairs being on one side of said hoistways and said transition section and the other of said pair being on the other side of said hoistways and said transition section;
• and
• a plurality of elevator cars, each having guides for engaging said rails, each selectively engageable by said car couplers, said cars being engageable by the corresponding one of said transition means so as to be moved between the upper end of the lower one of said pair of hoistways and the lower end of the upper one of said pair of hoistways.