ROUTE NEAR THE FORTY SEVENTH AND FORTY-NINTH PARALLELS. 55 



TUNNELS. 



In forming a judgment upon the practicability and length of time required to execute a tun 

 nel, the only safe guide is the result of well-tried means of excavation. 



When the question is the construction of a tunnel of several miles in length through rock, 

 the depth from the surface heing so great that shafts cannot he resorted to, the tunnel is only 

 practicable if some machinery can be applied to the excavation so as to bring its time of com 

 pletion within reasonable limits. The rate at which rock excavation could be made in it, by 

 the only means as yet successfully tried, would be so slow that the project would be considered 

 entirely impracticable. It does not appear that any of the machines invented for this purpose 

 have as yet proved successful, and no tunnel project depending upon their use can be con 

 sidered practicable until they have proved successful in trials of every kind. 



In hard rock, where continual blasting is required, the rate of progress may be taken at 

 10.5 inches every 12 hours. On the Black Rock tunnel, Reading railroad, through graywacke 

 slate, the progress was but little more than 0.6 of a foot every 24 hours, or 2,387 spaces of 12 

 hours each, for constructing 1,782.5 feet in length of the tunnel. 



In the Blue Ridge tunnel, on the Virginia Central railroad ; the progress has been less 

 than two feet per day of 24 hours. 



Tunnels two, three, and four miles in length, in rock or partly in rock, at depths exceeding 

 1,000 feet below the summit, in severely cold climates, at great distances from thickly in 

 habited districts, form serious objections to any route. 



The more southerly passes of the Rocky mountains partly explored, in connexion with this 

 route, have the advantage of not requiring tunnels. 



ESTIMATE. 



Governor Stevens s estimate of the time required to build the road cannot be founded upon 

 the experience of any great line of railroad built in the United States. 



The estimate of 25 per cent, to the cost at eastern prices from the Bois des Sioux to the Rocky 

 mountains, and thence to the Pacific of 40 per cent., is, in my judgment, too small an increase. 

 It would have been safer, probably, to have added 100 per cent, to the cost at eastern prices, 

 from the crossing of Milk river to the Pacific. Under this supposition, the corrected estimates of 

 $105,076,000, of $112,121,000, of $105,091,000, and of $129,806^000, would have added to 

 them $30,690,000, $33,750,000, $30,690,000, and $41,440,000, and would become 



Cost of road to Seattle by the Yakima Pass, using the long tunnel, 1,875 miles.. $135,766,000 

 Cost of road to Seattle by the Columbia valley and the Cowlitz river, 2,025 miles 145,871,000 



Cost of road to Vancouver, 1,864 miles 135,781,000 



Entire system, St. Paul to the Columbia, with branches down the Columbia and 

 across the Cascades, and a connexion from Seattle direct to the Columbia river, 



2,175 miles, at a cost of 171,246,000 



To the above original sums Governor Stevens adds for engineering and contin 

 gencies 5,000,000 



It does not appear whether equipment is included in the estimate ; if it is not, about $3,000,000 

 should be added to the above sums on that account. If a full equipment has been included, 

 $10,000,000 should be subtracted from each of the preceding sums, to bring the estimate in 

 accordance with those of the other routes ; and under this latter supposition the estimate finally 



becomes 



Cost of road to Seattle by the Yakima Pass, using the long tunnel, 1,875 miles. $130,766,000 



Cost of road to Seattle by the Columbia valley and the Cowlitz river, 2,025 miles 140,871,000 



Cost of road to Vancouver, 1,864 miles 130,781,000 



Entire system 166,246,000 



