Cylinder is for constraining part in assembly!!!

This is unfinished 3D model of Tower Crane, I designed as much as I could just by looking at images of tower cranes on internet. I over dimensioned most of model, as at first i had idea to try to make it in plastic. Most of cable work is unfinished as I do not have enough info about cable system. If anyone have informations that I need to finish this design, please contact me.

NOTE: Image of explode of assembly with part names on it is uploaded with assembly part.NOTE: In this design I didn't use real profile dimensions for steel beams, but in .prt files profile dimensions are editable in sketches.NOTE: Design is based ONLY on photos of tower cranes i found on internet so do not take it seriously.

So far assembly of this model consist of 20 parts (more will come as model get more details):1. apex2. apex rear conector (connection between 'apex' and 'rear pendant counterjib conector')3. cabin4. cable conector (connection between two 'rear cables' holding counterjib)5. counter weight segment6. crane body segment ground base (ground segment)7. crane body segment (repeating segment)8. crane climbing segment9. crane cabin segment10. crane jib - base (jib segment connected to 'crane cabin segment')11. crane jib last (end of jib segment)12. crane jib main (repeating jib segment)13. motor (motor behind cabin)14. fore cable (repeating cable that hold jib)15. fore cable conector (connection between `apex` and `fore cable`)16. fore jib connector (unfinished part, connection between 'crane jib main' and 'fore cable')17. rear cable (repeating cable that hold 'counter weight segment')18. rear pendant counterjib conector (connection between 'rear cable' and 'counter weight segment', and 'rear cable' and 'apex rear conector')19. trolley (trolley with cage and long cable)20. trolley sc (trolley without cage and with short cable)21. ASSEMBLY (part only, due to some error I was not able to make it in STEP format)