The Crane Mystery

There's this question that's been bugging me for over a month. It's a fairly simple question about a fairly common object in a city landscape, and yet it's an absolute mystery to me as to why I cannot come up with a believable solution. I've brought it up in ever-day conversation with friends and colleagues, hoping their answers might lead me to a justifiable answer. I've avoided Googling the answer for over a month, because some things in life just shouldn't be so easy. It's a fairly pleasant feeling to keep your mind pondering over such a simple question, and so the urge to pen this post.

How are cranes transported and constructed?

Take a minute, and visualise the size of these things. A crane is practically just two very long lines; one vertical steel pillar holding a similar horizontal one at the top. Moving them from place to place is difficult, and funnily enough, I've never seen a half-constructed crane.

Here's a list of answers I've come across.

• Break the vertical line into chunks, say 5 pieces, and place one on top of the other; but wait, won't you need another crane to lift the second part on top of the first?
  Clearly you can't just break it into pieces.
• The vertical part of the crane is one piece that increases/decreases length the same way a fireman's ladder does. So, the 5 pieces all fit in the size of one and magically rise out of the chunk below it.
  This seems far too complex in terms of design, and mechanically demanding.
• Since these pillars are made of 3 meter long steel tubes, you build the vertical pillar layer by layer. You construct the horizontal one in the same way at ground level and attach wheels(?) to lift it up, sliding up until it reaches the top of the vertical pillar.
  This just doesn't seem right. Lifting a horizontal pillar from the ground till the top with a counterweight on the other side defies gravity.

No answer leaves me satisfied. Do you know how cranes are transported and constructed?

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Ps. This question makes for great conversation!