To get the control cab of a tower crane, the operators have got to climb a foot-wide ladder welded from thin round steel pipes for about two minutes (this of course doesn't include the time it takes to get from the ground to the base of the tower crane). Those without sufficient strength and skill won't be able to make the ascent.
以塔吊手來說，從基座要爬到操作室，得在寬僅一尺、以細圓鋼管鑄成的內梯上爬個兩分鐘（不包括從地面爬到吊車基底的時間），沒有健壯的體力和好技術，一般人還真爬不來。