Pros of this design:
+ Any number of floors, with any distances between individual floors.
+ Being able to summon elevator to any floor.
+ Being able to go straight to any arbitrary chosen floor.
+ Being able to detect if the carriage is present on the current floor (useful for safety doors, bells and such).
+ Fairly small footprint.
+ Can be extended up or down at any time.
Cons:
- This design can't have a second "ceiling" carriage, it's incompatible with the work logic.
- Current implementation is a bit slow - it needs to send a redstone signal to the target floor and back before the carriage starts moving.
- Shaft walls aren't 100% solid, some redstone will be visible.
