Gable Bottom cars

Gable bottom car

Gable Bottom cars are side dump cars that have a upside down “V” piece of steel plate in the inside bottom of the tub to force the muck out the two side doors. 

 These cars were first introduced in Bisbee in 1908 with the purchase of 200 cars from Arthur Koppel co. by Copper Queen Consolidated. Another type of gable bottom car, known as a porphyry car was later purchased by Calumet & Arizona and was in use by 1930. They continued to be used until the late 1940’s or early 1950’s. The name porphyry car comes from its use mining the east ore body in the porphyry. This car was of unknown manufacture and could hold 4 ½ tons.

Cross section of a gable bottom car showing “V” inside car bottom

  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.

Koppel version car circa 1900’s

 

Gable bottom Koppel

 

Specifications

 
   

Capacity

21 cubic ft

Gauge

20" 1/4

Overall length

6’-1”

Outside width

2'-8"

Height

3'- 10"

Coupler type

 M.C.B. Automatic

Bearing

Siamese roller bearing

Dumping a porphyry car by hitting latch with a double jack circa late 1940’s

Porphyry Car Specifications

Capacity

                                                                  72ft

Inside length

                                                                     9'

Outside width

                                                                   4'7"

Height

                                                                 4'10"

Over hang

                                                                    17"

 Coupler type

Automatic (No.1 national midget)

Pocket and chute designs for the porphyry car

References
Bisbee Daily Review March 13 1910, no. 266 vol. XII p.1
Lavender H.M. Mining Methods at the Campbell Mine of the Calumet & Arizona Mining Co., Warren Ariz. Information circular 6289,April1930, fig 3,4,10
Mining and Scientific Press July 1908 Vol. 97 p66
Procedure of Safe Practice for Haulage 1947, Phelps Dodge Corporation p.10-12
Richard Graeme IV 2010, pers. comm., 8 February
Richard Graeme III 2010, pers. comm., 2 February
Transactions of American Institute of Mining Engineers 1916 Vol. LII pp. 466-467
Unknown ,“Mine Car Data” Phelps Dodge Corporation, Bisbee, Arizona (blueprint)

 

graemite@hotmail.com.

© 2013 by Doug Graeme