PASS OF THE COLUMBIA RIVER. 
187 
ment of the line in deflection to avoid it, or the severity of the changes of direction needed in 
curvature. I shall report more fully in regard to this matter after a careful examination on my 
way back. 
On so important a line as the proposed Pacific railroad, I should not recommend curvatures of 
less than two thousand feet radii, or a reverse within five hundred feet of the tangent point, save in 
.extreme or nearly impracticable cases, which the latter is not. The tunnel would not exceed 
seven hundred feet, and would cost, at eastern prices, say sixty-five dollars per lineal foot—a 
high estimate, when the character of the ledge is considered. The length of this tunnel, working 
both faces, does not hinder its construction in a short space of time; and I am by no means 
certain that it is absolutely necessary. 
The greater facilities for applying large forces of laborers upon the river line, and thus for¬ 
warding it to an early completion, is an important item in obtaining a result; for the use of the 
rail in carrying supplies into the interior bears very fully upon the question of location for the 
first five hundred miles of the line, and will rule the cost of those portions of the route at a 
distance from communication; therefoie, as abundant means of transportation as exist, by the 
navigable waters of the Columbia, should give their aid by artificial means for reaching the far 
interior, where leagues of prairie and many miles of shallow open cuttings will be ready for 
the rail before the great summit sections of the mountain passes are excavated. Contractors will 
study these questions very fully, as they materially influence both the cost of the road and the 
lime of its completion* 
^ ^ ^ ^ ^ ^ ^ ^ 
You have directed me to estimate upon a bridge across the Columbia, at some point between 
Vancouver and the Cowlitz, for the purpose of affording the valley of the Willamette railroad com¬ 
munication with the terminus of the route by the Snoqualme. It is impossible to arrive at even 
an approximate estimate of the cost of such a structure until the width of the river at the 
favorable point is ascertained, the distance across the flats and their quality, the depth of sound¬ 
ings both of mud and water, the force of current, the effects of ice in spring freshets, &c., all of 
which must direct in planning the mode of bridging. 
I believe, however, that the river is shallow, and that a plain bridge of piling can be safely 
used for a large portion of the distance. Near the centre, by the aid of the coffer-dam, good 
piling foundations should be obtained for substantial piers of heavy masonry, and a few spans of 
Howe’s truss give free passage to the water. I should think the probability of danger from ice in 
freshets, either in lifting, piling, or crowning, not sufficient to deter us from attempting such a 
mode of structure; and, supposing the conclusions to be correct at the present rates of labor 
upon the Columbia, the prices of the work would range as follows, viz: 
FuAt-class piling structure, at 80 cents per square foot, on upper bridge surface, for 
a road-bed of 20 feet, is per lineal foot of road $16—5,000 feet (piling). $80,000 
Howe’s truss, at $60 per foot, 400 feet..... 24,000 
Draw and appendages. 25,000 
Two first-class, large' wing abutments; three deep-wa er piers and foundations; 
materials lor masonry transported on road from Puget sound, which cost, say 
$40 per perch. SO,000 
$209,000 
The Columbia can be bridged at the Cascades, and at several points above the Dalles, without 
obstructing navigation. *** ***** 
O O 
I am, with respect, your obedient servant, 
Cov. 1 . 1 . Stevens, Chief N. P. It. Exploration and Survey. 
F. W. LANDEll. 
