Early cars had and automatic tripping (dumping) feature.  The trip would be placed between the rails at the required dumping point. When the car was moved over the trip the mechanism would release the doors and the muck would fall out. After dumping, the shutting doors would automatically latch in place. This early type had a susceptibility to leak fine ore from the doors, especially when wet. This made messes along the drifts. The cars were difficult to dump with sticky material. Muck would hang in the car even when, the doors were held open. To release the muck two men would have to rock the car from side to side while the doors were held open. Eventually, the doors would become bent and could be only closed by repeated hammering.    After only a few months the difficulties caused by the design problems triggered a search for a new type of car. In 1909 a 22 cubic ft. rocker dump (Queen Rocker?) was introduced. The porphyry car had a long latch that would keep the door shut. To dump trains the motorman would stop the first  cars over the pocket. One man would be on each side of the train, they would hit one end of the latch with a eight pound double jack opening the doors. Once the car was empty they would hit the other end with the double jack closing the door.  When the doors were stuck open they were supposed to use a boulder hook to open the  door letting the blocking material fall out. It was more common to grab the door with a bare hand and open them. This practice was unsafe. To dump the cars, a pocket  with grizzlies on each side of the car is necessary. Only a single example of a Bisbee gable bottom car survives, It is of the early style and was located at the bottom of the Galena mine dump behind Tintown until the 1980’s. This car was later acquired by a person in Douglas Arizona.