66 Book of Engineering 



the Andes. On the eastern side, in Argen- 

 tina, the ascent is fairly gradual, although 

 towards the end there are some stiff gradients 

 laid down upon the rack-rail principle, but 

 onjthe Chilean side of the Andes there is 

 a sheer drop of something like 3,150 feet, 

 whilst in 46 miles to the coast there is a 

 difference in levels of 8,000 feet. 



The tunnel was cut through the last two 

 miles of the mountains and the traveller 

 may be impressed to think that he is 

 proceeding at a depth of 2,630 feet below 

 the old mountain road. 



Over 2,000 men were employed on the 

 two-mile tunnel cut through some of the 

 hardest rock that drills have ever tackled; 

 indeed, the first drills would make no 

 impression and time was lost whilst a fresh 

 battery was obtained. Then, with the aid 

 of dynamite, the work went on steadily, 

 the men being divided into eight-hour 

 shifts so that the boring was continuous. 

 It was most trying work for these poor 

 fellows. Two miles above sea level meant 

 rarefied air, and it was bitterly cold. Yet 



