The tiered structure of Pocalo makes travel from one province to the next a challenge, unless you can hop on an elevator. Large elevators, like the one pictured here, are designed to carry a great deal of freight and several passengers (it seats around 150 people, so about the same as a medium-sized commercial airplane) among multiple provinces.
This particular elevator services four levels, and does much of the heavy lifting (ha ha) for getting agricultural foodstuffs distributed to the northern regions of the provinces. Merchants also use this elevator to move their wares around, perhaps selling medicines in one province, picking up some local foods, and moving on to sell those in a different province.
There are much smaller elevators dotted throughout the provinces, generally just ferrying between two levels. Most of these are concentrated in the upper provinces; the lower provinces (i.e., those at ground level and below) have relatively few elevators. This has more to do with population density than anything else; large swaths of the lowest two provinces are flooded, rendering them mostly uninhabitable.
While elevators have connected the provinces for around 300 years, this type of large freight elevator is relatively new technology (maybe 100 years old), and has accelerated cultural exchange and homogenization. While the people of each province still have their own distinct accents, clothing styles, foods, and so forth, basic necessities are widely distributed wherever you go.