Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 1, Pt. 2

RAILROAD PRACTICABILITY OF SNOQUALME PASS.
From the crossing of the Columbia to the commencement of the pine timber, a distance of
ninety-six miles, the general character of the valley is wide, open, and terraced-the ground
of sand, gravel, or loose stones; but little clay or vegetable mould; curves easy, long stretches of
straight road, perfectly practicable. In this distance there are five points where the hills come
close to the river, making at most ten miles of side-cutting necessary. This cutting is generally
in earth, loose stone or trap rock, easily broken into blocks. In addition to these points, the
last eight miles of the ninety-six will be principally side-cutting in earth, gravel and sand, the
work light, and no very high side-slopes. In the first eighty miles from the Columbia the grade
will be twelve and a half feet to the mile; in the last sixteen miles it will be eight and a half feet
to the mile.
By keeping thus far the north bank of the Yakima, the only bridges of any consequence required
will be two over streams each about seventy-five feet in width. At some place in this vicinity
it would be advisable to cross to the south bank of the Yakima, which is here about forty yards
wide, good crossing easily found, plenty of timber on the spot, and stone for masonry within
twenty-five miles by water. The road now keeps to the valley twenty-one miles farther on;
four miles beyond Ketetas, passing through an open pine woods; soil light, sometimes gravelly;
about two miles side-cutting; grade eight feet to the mile.
If the short tunnel be used, the road must at this point leave the valley, take a side location
on the northern slope of the mountain bordering the valley on the south, and ascend eight hundred
and ninety-five feet in eighteen and a half miles, giving a grade of 48.4 feet per mile in ffty per
cent. rock. The plateau of Willailootzas, one mile long, will be entered by a curve with a radius
of about 2,000 feet, the road passing along the north bank of the lake, with side location, in eighty
per cent. trap rock, easily worked. This lake should be partially drained; its shores are steep
and of broken stone. There will be some little difficulty in preparing a proper depot for the workmen, tools, &c., at the entrance of the tunnel. The tunnel, about 4,000 yards long, will pass
through solid rock (silicious conglomerate,) and will debouche on the western slope, at an elevation of about 3,000 feet above the sound at Seattle. The road must now have a side location
on the mountain spur bordering the valley of the Nook-noo, in about seventy per cent. rock,
generally conglomerate; follow this valley twenty-nine and a half miles, then take the summit
and northern slope of the low ridge separating Lake Mowee from the valley of the Snoqualme,
and from that taking a spur running from the Nook-noo falls to those of the Snoqualme, reach the
latter falls a distance of forty-five miles from the tunnel; all in side-cutting, with rocks as above.
The grade will be 59.8 feet per mile. With reference to this stretch of forty-five miles, and
that of eighteen and a half miles on the eastern slope, leading to the tunnel, it is to be observed
that the grades given above are on the supposition that a continuous grade can be obtained; but
it must be expected that the grade will necessarily be broken, and be higher than the estimate in
many places.
From the Snoqualme falls to Seattle is a distance of about thirty miles, of which the first ten
must have a grade of 20 feet per mile, at most, and the remainder, twenty, pass over quite a level
country.
If, instead of a tunnel from the level of Lake Willailootzas, we consider a tunnel from the
level of Lake Kitchelus, the case will be as follows: Commencing at the point eighteen and
a half miles east of Willailootzas, there will be eighteen and a half miles with a grade of 15.2
feet per mile, and but little side-cutting, through a thickly timbered country as far as Kitchelus.
The divide must now be pierced by a tunnel 11,840 yards long, of a character similar to the
one considered above. The grade to the Snoqualme falls will be 46.3 feet per mile; all other
circumstances unchanged. The greatest grades will probably be 80 feet to the mile in the case
of the.short tunnel, and 60 feet in the case of the long tunnel, and both for short distances.
A line along the Columbia river to the sound will be necessary, even with lines both down the
Columbia river and through the Snoqualme Pass.
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