They come one section at a time by truck, and the crane cab climbs each section as they are hoisted up by the last section.

The most dangerous time for cranes is the time between hoisting and bolting the next section on (or the reverse during disassembly).

One fell in Manhattan a couple years ago during disassembly. wsatlaw.com/manhattan-crane-accident-new-safety-r…

There are new procedures now after that investigation.