7.3　Stockyards Equipped with Loading/Unloading Bridges or Gantry Grab Cranes

7.3.1　The track length of loading/unloading bridges or gantry grab cranes shall satisfy work travel requirements，and a buffer travel of 10m and a stop shall be provided at each end.

If no retaining wall is constructed at the track side，the distance from the top of the track to the grade plane should be 0.5m-1.0m.If retaining wall is constructed at the track side，it shall be 1m higher than the top of the track，and shall be at least 0.8m away from the track.

7.3.2　The height of stockpiles in the stockyards equipped with loading/unloading bridges or gantry grab cranes shall be 1m lower than the underside of the grab and 0.5m lower than the underside of the cab when the grab is at its highest position limit.The normal traveling range of the trolley to position limit shall not be less than 1.10m.

7.3.3　Loading/unloading bridges or gantry grab cranes shall have receiving hoppers provided at the fixed leg side，and associated grade-mounted belt conveyors shall be equipped.at this side.

7.3.4　Standbys may not be provided for loading/unloading bridges or gantry grab cranes，however，if only one loading/unloading bridge or gantry grab crane is equipped，standby reclaiming machines（e.g.，bulldozers，single bucket loaders）shall be provided.