tower crane machine, operators cab and load concrete weights

arm assembled balance behind blocks blu build building buildings cab cabin cables carry compensate concrete connect connected construction controls counter counterweights crane cranes dogger engine extends fixed greater height heights hook hooks horizontally industry installation jib lift lifting load loads machine main mast material materials mobility motion motor mounted move moving operating operator operators place rear rigger rolling rotate sections shift sky slab slewing steel structures supporting suspends swamper telescopic top tower transport trolley trussed turntable type unit weights