That must be kit 78030 from 2013 with new parts based on the new tooling from 1979. I am in the process of building kit 78031. You can get detail sets from Eduards, Gold Metal Models and Toms Models. Plus decking from Artwox and other vendors and barrels from Master or RB.
I know you can just purchase the railings for this kit, I believe Eduards sells it or it maybe Tamiya. I haven't seen any offers with just cranes but there maybe generic being offered at online stores or e-bay.