Comment by mauvehaus

The book Men Of Steel is about the company that erected the steel for the towers. It's highly worth reading and it talks at length about some of the challenges in not only the erection of the buildings, but the problems caused by the sheer scale of it.

The four cranes on each tower that you can see in the photos were a scaling up of a proven design and it didn't scale up well. They had tons of problems with them breaking down.

There were also some plans to do automated welding that came to naught. They had to fall back to manual welding after they couldn't get the automated process to work.