Go for Minimum -weight Design.And warn(with intelligent load-cell data) not to overload at centre-span - where overloading is most vulnerable.
Pay a premium for use of High-Tensile steels to minimize all overhead metal works.
Use Electrohydraulic twin drive for two rails on Long travel. Accumulators will minimize electric Motor deadloads.
Possibly these same Electro-hydraulic power units operate Cross/Hoist duties.
Speed : Operate combined Long+Cross+Up/Down movements under PLC LOgic.
Operation : Minimise need for operator to control from top.Use mostly wireless from floor. Warning/Control/Shutdown automatic and informed in feedback link to operator and Blackbox!