of the mountain, however, prove it to be 212 feet higher than Sugar Run Gap, and, to reduce it to a level with the surface of the ground at the latter point, which is 120 feet above the grade of the adopted line, it would require a tunnel 1¼ miles in length, to be constructed under very disadvantageous local circumstances.
Cedar Swamp Gap, still farther south, is 53 feet lower than Bob's Creek Gap, but it falls off on each side so gradually that it could not be reduced conveniently more than 40 feet.
Neither of these points, therefore, which are the only passes worthy of notice south of the Portage Railroad that lie within the region over which a direct line to Pittsburg must necessarily traverse, afford depressions that will compare favorably with those farther north; nor does the ground leading to them, east or west of the mountains, offer equal facilities to obtain a line of uniform ascent to the summit. The distance from the Conemaugh is too short to overcome the elevation with the gradient used on the western division, and, from the Juniata, the greater height to be ascended would continue the line so long upon the mountain steeps that it would be exceedingly expensive to procure a roadbed with a gradient even higher than 80 feet per mile.
From the foregoing description of the most favorable mountain passes, it will be seen that Sugar Run Gap offers the greatest facilities to cross the Allegheny.
It now becomes necessary to consider in what direction the Road can be carried thence to Pittsburg. From an inspection of a map of the State it will be seen that a straight line, drawn from this gap to Pittsburg, will fall on Munster, Beulah, and follow the valley of Black Lick for nearly its whole extent, and intersect the Conemaugh near Blairsville; thence it crosses the country lying within the elbow formed by the Kiskeminetas and Allegheny rivers, passing the Loyalhanna and Crabtree waters, and following, generally, the high and broken ridge parting the Allegheny and Monongahela rivers. That line, which would approximate most nearly to this course, would—all other things being equal—be the most desirable for the Road.
The operations of the different corps, on this division, have been confined to surveys that were necessary to determine the point of crossing the mountain and to the regions between the Conemaugh and Pittsburg, west of the Chestnut ridge. Our examinations have not yet been sufficiently extensive to enable me to give a full description of that part of the country between the mountain and Blairsville, and I shall therefore leave it for a future report, with the simple remark that, from the information before me, I am satisfied that a practicable line may be obtained by the valleys, either of the Black Lick or Conemaugh, within the maximum gradient used upon the western division.
The district of country over which it will be necessary to carry the road from the Conemaugh to Pittsburg is one of remarkable intricacy. It lies wholly within the coal measures, and has, at some period, evidently been nearly a level plane of vast extent, covered by the ocean. The discharge of the waters from this wide spread field seems to have been sudden, forming numerous circuitous channels in every direction, cutting deeply into the soft horizontal strata of this region, in their descent to the tributaries of the Ohio, leaving the intervening ridges washed into so uneven a surface as to render the passage of a railroad along them entirely out of the question. A line following the Conemaugh—which bears northwest from Blairsville—to the Allegheny would avoid this difficult country, but the length of the route would be increased fully 50 per cent., and it is, therefore, inadmissible.
A route with higher gradients than those adopted on the Juniata throughout this division seems to be called for by the topography of the country.
In his report upon the western division, Mr. Miller gives the following account of the surveys, conducted under his direction by Messrs. Day and Pemberton, his principal assistants: "If a straight line be drawn from Blairsville to Pittsburg, it will be seen that Turtle creek is the only stream that approximates to the proper course of the road, whilst the Loyalhanna, the chief tributary of the Conemaugh, crosses it nearly at right angles, and Spruce Run, Roaring Run, Porter's Run, Beaver Run and others intersect it at various angles of obliquity. Much time and labor were bestowed by Mr. Schlatter and his principal assistant, Mr. Roebling, upon the investigation of this district, and their maps and profiles, loaned to us by the Canal Commissioners, have been of much service in our examinations. From a careful investigation of Mr. Schlatter's preferred route on the ground, it appeared possible to avoid some of the most formidable obstacles which he encountered by adopting a higher gradient than his maximum of 45 feet per mile, and by a reasonable increase of distance at a few points.
"Our trial lines confirmed this, and, in the location made, a maximum of 1. in 100, or 52–8/10 feet per mile, has been used at several places. The cheapness of fuel throughout the whole extent of the western division renders this increase of gradient less objectionable than elsewhere. Bituminous coal, of the best quality, is everywhere abundant, and can be delivered at the depots at from 56 to 84 cents per ton."
The principal changes made in the route referred to in Mr. Schlatter's report Mr. Miller describes as follows:
"Upon the White Thorn our line keeps the left bank, entirely to its mouth, avoiding a tunnel of 600 feet, leading into the valley of Buck Run, and a high bridge over White Thorn creek, and reducing that over the Loyalhanna, from 90 to 50 feet in height. West of Buchanan's summit we run level round the hill, between Porter's Run and Beaver Run, avoiding the Still House summit entirely, where a tunnel of 1,000 feet was proposed, with a cut of 70 feet at its western end, running out to grade in a distance of 1,700 feet.
"Passing Burnt Cabin summit, by a deep cut, the line descends along Turtle creek to the Monongahela.
"Below Murraysville the creek makes a double bend, like the letter S. The former line crossed one of these bends, by a tunnel 600 feet long, whilst ours crosses the other by a short, deep cut, following a remarkable pass by which the hill is nearly cut through. These changes have reduced many of the deep cuts, avoided several bridges, saved three tunnels, and reduced the length of a fourth, amounting in all to a reduction of 2,300 feet of tunneling."
After reaching the Monongahela, two routes present themselves, one following the bank of the stream to Pittsburg, and the other ascending along the slope of the river hills, enters a valley leading by Wilkinsburg and East Liberty. Thence, following this valley, it descends Two Mile Run, and enters the city on the Allegheny side. The latter, though the longest route, and requiring gradients of 50 feet per mile, has been adopted as it presented the only apparently feasible route by which a connection could be formed with a road extending towards the great west.
The comparative cost of grading and damages, upon the two lines, would be rather in favor of the route adopted.
A line has also been located from the junction of Turtle and Bush creeks, which passes up Bush creek and through Greensburg to Bernhard's summit, thence by the valleys of Fourteen Mile Run, Sauxman's and Magee's Runs, to the Conemaugh, at the gap through Chestnut ridge.
If the Conemaugh route, by Johnstown, should be adopted, the line by Greensburg will be about 3¾ miles longer than that by Turtle creek, but passes east of the Loyalhanna, over much more favorable ground than any other line examined.
Its advantages, in relation to the local trade of a rich and populous section of country, west and east of Chestnut ridge, through the gap formed by the Loyalhanna, give it strong claim for consideration.
Whether the increased length of the line and the difficulties west of Greensburg will be sufficient to counterbalance these local advantages we will leave undecided until the comparative estimates have been fully made out. Another line was traced, leaving Greensburg and passing into Ligonier valley, through Chestnut ridge, at the Loyalhanna Gap, thence north of this ridge along Coalpit and Kendrick's Runs, to the Conemaugh, which resulted unfavorably.
Further
