active activities apology broken communicating communication equipment inconvenient information informing limitations limited limits message not-working out-of-order safety sign sorry to-be-fixed unfortunate unusable unworkable useless warning wording attachments bucket bucket-loader cab construction construction-equipment differential-steering digger earth-excavation earth-mover engine-powered excavate excavation excavator fixed-straight-wheel-alignment four-wheeled front-end-loader front-loader frontend-loader industrial labor-saving lift-arms lift-mechanism loader machine machinery maneuverability manoeuvrability mobility mover multi-purpose operator payloader powerscoop rigid-frame scoop scoop-loader skid-loader skid-steer skid-steer-loader skidsteer small tires transport tyres vehicle wheels zero-radius-pirouette-turning