LA PAZ and EL ALTO, Bolivia — In these two cities, geography and rank stand in inverse relation. La Paz — the seat of government, old money and a lighter-skinned elite — sits in a valley. Above it on a high plateau is the frenetic city of El Alto: poorer, younger and generally darker-skinned. La Paz has always looked down on its upstart younger sibling above.

Now, that relationship is being challenged, and this urban Möbius strip, where down is up and up is down, is getting a new twist. A mass-transit aerial cable-car system, a cross between a ski gondola and an elevated train, is being installed to better connect them, chipping away at the physical barriers and possibly some of the psychological ones.

The first line in the system, stretching from an area near the center of La Paz to just beyond the lip of the plateau into El Alto, began carrying riders on May 31. Another line is expected to go into operation in September, and a third the next month — just in time for an election on Oct. 12, in which President Evo Morales is running for a third term.

Mr. Morales, who ordered the construction of the cable-car system, recently announced that he would build five more lines. It is part of a master plan that Cesar Dockweiler, the general coordinator of the project, said could eventually include up to 18 lines: stretching deep down the valley into La Paz’s Zona Sur, or Southern Zone, where the wealthiest live, and far across the plateau, home to some of El Alto’s poorest.