7.4　Warehouses Equipped with Bridge Grab Cranes

7.4.1　Where railway unloading bay is constructed within the span of bridge grab crane，the headroom clearance from the railway centerline to the columns of warehouse shall be minimum 2.5m（for unloading on one side），and crane cab should be arranged at the side near to railway unloading bay.

7.4.2　Warehouses equipped with bridge grab cranes should be of semi-enclosed structure，and may be of totally enclosed structure for stringent environmental protection requirements.

7.4.3　Bridge grab cranes should have minimum span of 22.5m.

7.4.4　Grab traveling height of bridge grab crane shall be 0.3m-0.5m lower than its limit height，and shall be at least 0.5m above the top of the stockpile or the hopper when the grab is opened..The normal traveling range of the crane to the safety rule shall not be less than 1m，and the normal traveling range of the trolley to the traveling limit shall not be less than 0.5m.

7.4.5　Where more than two bridge grab cranes are erected on the same track，the average operating length of each bridge grab crane at crane traveling direction should not be less than 40m.Power supply to each bridge grab crane shall be individually turned off.