IT NX ELS TIIKoiiiii HAKI> KorK 



119 



Hauling. Two different systems were employed for haul- 

 ing the spoil and construction material in the St. Gothard 

 tunnel. To remove the spoil from parts Nos. 1 and 2 a narrow- 

 gauge track was laid on the floor of the heading, and the care 

 were hauled by horses, the grade being descending from the 

 fronts. These narrow-gauge cars were dumped into larger 

 broad-gauge cars running on the track laid on the floor of the 

 completed section and hauled by compressed air locomotives 

 (Fig. 59). To raise the incoming structural material from the 

 broad-gauge cars to the narrow-gauge care running on the level 

 above, hoisting devices were employed. 



Method of Strutting Roof, St Gothard 

 Tunnel. 



Sketch Showing Arrangement of Car 

 Track*, St. (iotnmrd Tunnel. 



Busk Tunnel The Busk tunnel, 9,094 ft long, was built 

 between Busk and Ivanhoe stations, on the Colorado Midland 

 R.K. in Colorado. Fig. 60 is a transverse section of the 

 tunnel ; it is for a single track, and is 15 ft wide and 21 ft 

 high. 



Material Penetrated. The material through which the 

 tunnel was driven was a gray granite of irregular character. 

 In some places the rock was found extremely hard to drill and 

 blast, and stood perfectly uj>on exposure to the air, while in other 

 places, where it seemed at first equally as hard and firm, it dis- 

 integrated upon exposure, and it was found necessary to timber 



