94 ROUTE NEAR THE THIRTY-SECOND PARALLEL. 
grade of 105 feet per mile for five miles, to the next summit, passing the dividing ridge by a tun- 
nel of 4,100 feet in length, and whence, after three miles of light grade, a descent by the grade 
of 105 feet per mile for five miles is made to the valley of Racoon creek, by which, and the 
valley of the Three Forks creek, the Tygart’s Valley river is reached in fourteen miles more, at 
the Turnpike bridge above described, and 1034 miles from Cumberland.” 
The foregoing extract exhibits in a few words the physical obstacles to be overcome. It will 
be seen that a gradient of 116 feet per mile, both ascending and descending, is required—in the 
ageregate amounting to twenty miles—and that in both directions there are also thirteen miles 
more with gradients exceeding 100 feet per mile.” 
Two important remarks upon the characteristics of the railroad from Valparaiso to Santiago, 
which will be found in the preceding extract from the report of Allan Campbell, Esq., are equally 
applicable to the route of the 32d parallel. The first is the favorable character of the approaches 
to the mountains, by which no numerous secondary ranges and deep intervening valleys are to 
be crossed, as in the railroads crossing the Alleghany mountains; and the second is, that the line 
will be free from the evils resulting from snow and ice, which diminish the adhesion of the 
engine to the rails, and reduce its effective power. Not only are these two remarks fully appli- 
cable to the route of the 32d parallel, but the features of the mountain passes are even more 
favorable than those of the route discussed by Mr. Campbell. 
There will be more snow and ice in the Tah-ee-chay-pah Pass than in any other on the 
route of the 32d parallel; but there is no probability of their being found in sufficient quantity 
to obstruct in the least the working of the road. In the absence of positive information upon 
this point, the examination which follows may give some general indication of the climate there. 
The absence of snow and ice in these passes is especially important with the high grades pro- 
posed to be used. These can in every instance, except one, (the San Fernando Pass, over four and 
perhaps eight miles,) be reduced by side location to grades in use on several principal railroads. But 
cars are carried safely over grades nearly double the greatest here proposed for temporary use, 
and the increased cost of employing additional engines over these portions of the road is not in the 
- least serious, compared with the additional expense and loss of time required to secure easier 
gradients. 
The winter temperature of San Francisco is 50° Fahrenheit. 'The Tah-ee-chay-pah Pass is 
about 8° south of San Francisco, and at the same level would have a winter temperature of 53°. 
The elevation being 4,000 feet, would give, by the usual rule, a temperature from 13° to 15° 
lower, or a mean winter temperature of 40° or 38°. It is probable, however, that it is some- 
what lower than this, which is about the mean winter temperature of Fort Monroe, Old Point 
Comfort, Chesapeake bay. The mean winter temperature of Charleston is 50°, and that of the 
summit elevation of the railroad route westward to the Mississippi, 1,400 feet above the sea, 
is about 45°. 
The mean winter temperature of Fort McHenry, Baltimore harbor, is 32°.7; that of the sum- 
mit elevation of the Baltimore and Ohio railroad, 2,600 feet above the sea, should be about 24°, 
which is 14° or 16° lower than that obtained for the Tah-ee-chay-pah Pass. 
There is deep snow in the Tejon Pass, but from the open character of the Tah-ee-chay-pah 
Pass, and its greater distance from the junction of the two chains of mountains, the snow and ice 
found there will not probably be seriously disadvantageous. 
GENERAL REVIEW. 
Among the general considerations which determine the position of the route near the 32d 
parallel, the most prominent are the low eievation of the mountain passes, and their favorable 
topographical features, as well as those of the table-lands, embracing over 1,000 miles of the 
route; the favorable character of the surface generally, by which the most costly item of con- 
struction in railroads, the formation of the road-bed, is in a great measure avoided; the short- 
