Alley factory industrial industrial works old factor old works windows works backhoe loaders bulldozer carry hard work machine machines maquinas obras work work site angles building building construction building site building work buildings construction construction site construction work crane danger height heights high metal work pipes railing rails safety scaffolding security steel scaffolding tall work-safe workmen net netting safety mesh safety netting building-construction building-site building-work cabin cables construction-site construction-work hoist hoisting lift lifting light linear lines metal-work modern platforms raising skip steel-scaffolding workers working external lifts protected protection