Tower crane models and side questions

[Cartoondude135]

These two luffing boom cranes; what manufacture makes them and what model(s) are they? Once I get more info about these cranes, I can make them into 3d models.

Next, on a Liebherr trolley tower crane like this EG: How will you be able to enter the cab? I've never been on any tower crane before (or at least one like this), so the only theory I can muster up is there's a trap door in the floor of the cab. If you have pictures of this type of crane's cab's access door, show me.

Finally, why do some trolley tower cranes have what looks like a third wheel on it's trolley to have the lift cable run 4 times through the load block? Like, what's the purpose of that and how would this third wheel even work? On this Linden tower crane, it can be configured to have the cable run through the hook load block 2 times like most tower cranes. But sometimes, I see it configured with that third wheel on it's trolley to make the lift cable run through the load block 4 times.

 

[Knepptune]

I don’t know what model or brand the top pictures are.

On the liebherrs they have a door in the bottom and a door on top. You go through the cab to get to the top of the crane. I’ve never been in one so I don’t know exactly what it looks like.

The third sheave is so that you can run either a 4 or 2 part line. Use 4 if your lifting heavy and 2 if you need more winch speed.