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 being so great that shafts cannot be 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 grayAvacke 
slate, the progress was but little more than 0.6 of a foot every 24 hours, or 2,381 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 tAvo, 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 Avith 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 Avould liaA r e 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 $10-5,091,000, 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 CoAvlitz 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 Avhether 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 
