Part 3
Of the several routes proposed, I found no difficulty--after a careful inspection of the plans of the various surveys, made under the authority of the Commonwealth, and my reconnoissance of the country--in coming to the conclusion that the valley of the Juniata offered advantages for a line which, whether we consider the low gradients that may be obtained along it or its general directness, the desiderata required, is without a rival.
This stream has its source in the Alleghenies, and consequently severs, as it flows towards the Atlantic, all the secondary mountain ranges that lie east of them, and it heads opposite to the Black Lick and Conemaugh rivers, both of which sever those on the west, leaving the main Allegheny only to be surmounted, which would have to be encountered upon any other _direct_ route, in addition to many of the inferior mountain ranges. A more northern route, by the west branch of the Susquehanna (which has its source beyond the Allegheny mountains), would have encountered less elevation at the principal summit, but its great increased length precluded its adoption; while, on the other hand, a southern route, though not indirect, was equally objectionable on account of the rugged character of the country, and the high gradients necessary to overcome the numerous summits upon it. A partial examination of one of the proposed southern routes was made, which followed the Cumberland Valley Railroad to near Shippensburg, and thence, crossing to the west side of the valley at Roxbury, it passed through the Blue Mountain, by a long tunnel, into Path valley; thence, following around the point of Dividing mountain, it crossed this valley and passed through Tuscarora, by another tunnel, to the valley of Augwick creek. Thence it would have been traced between Broad Top and Sideling mountains, and up Dunning and Bob's creeks to the summit of the Alleghenies at Bob's Creek gap; or, turning west by Bedford, crossed the Alleghenies at the head waters of the tributaries of Castleman's river, where the mountain is still much more elevated.
A line leaving the Cumberland Valley Railroad at Chambersburg, and turning the end of Blue mountain, thence seeking the low depression at Cowan's gap in Tuscarora, would be too circuitous to compare favorably with the bolder line from Shippensburg, already described.
But that line would encounter engineering difficulties of the most formidable character; leaving out of view its objectionable gradients, and considering it in reference to its cost, and the local accommodations it would extend to a large portion of the State--at present in a great measure deprived of the advantages of the State improvements--(the strongest argument in favor of the route), it will be found that equal accommodations could be extended to that region with a _less_ expenditure of _capital_ by placing the main stem of the road on the Juniata, and running a branch along one of the comparatively level valleys that lie between most of the parallel mountain ranges that we pass.
The facilities that railroads offer for extending their benefits to remote districts by means of lateral lines constitute one of their chief advantages over canals, and should prevent the error, too frequently committed in locating leading routes, of turning from a direct course to accommodate local interests to the injury of the great object intended to be accomplished.
Other modifications of the Juniata route have been suggested, and their merits fully considered, but, upon examination, all of them tended to confirm our preference in favor of the river line.
These conclusions were communicated to the Board, and the general route recommended having been adopted by them, I proceeded at once to make arrangements to have the line surveyed throughout. For this purpose three additional corps of engineers were organized--one for Mr. Miller's division, under the immediate direction of Mr. G. W. Leuffer, to operate on the summit and western slope of the mountain, and two upon Mr. Foster's, the first of which was placed in charge of Edward Tilghman, Esq., to whom was assigned the district between Lewistown and the confluence of the Raystown branch and main Juniata rivers.
The other corps was given in charge to S. W. Mifflin, Esq., a gentleman of well-known professional skill and experience, to whom we committed the surveys of the region from the Raystown branch to the summit of the Alleghenies, embracing the most important and difficult district upon the whole route to Pittsburg.
These parties did not take the field until the close of July, but they prosecuted their examinations with so much energy and success that we were enabled to determine the general line of the eastern division in season to place the most difficult points upon it under contract in November of last year.
While these arrangements were in progress, the parties previously in the field were actively engaged in examining the country between Harrisburg and Lewistown.
At the instance of a number of gentlemen from Perry county, a line was tried up Little Juniata creek, leaving the Susquehanna at Petersburg, thence near Bloomfield and along Sherman's valley to Concord gap, where it passed the Tuscarora mountain, thence it followed Tuscarora valley to Shade creek, and down that stream to Augwick creek, along the valley of which it was carried to Drake's ferry on the Juniata. The advantage promised for this route was a considerable saving of distance. The result, however, demonstrated that not only would we have had to encounter gradients running up as high as sixty feet per mile, but the length of the line would be increased four miles by its adoption. It was consequently abandoned.
After a careful examination of the country bordering on the Susquehanna and Juniata rivers, a line has been located as far up as Huntingdon, which is believed to be the best that can be obtained.
If the valleys of these streams had not been preoccupied by other improvements, a route would have been selected differing somewhat in its details from that adopted. Even for the short distance that we are brought into close proximity with them, the cost of the grading of the Road has been greatly enhanced by the confined ground we have been forced upon.
The located line commences at the Harrisburg and Lancaster Railroad depot; thence, passing through Harrisburg, it follows the sloping ground between the canal and the capitol ridge four miles, when it crosses the canal and, touching the point of Blue mountain, recrosses and passes to the west side of the Susquehanna river by a bridge 3,660 feet in length, and 44 feet above low water at grade line, which enables us to place the road on the top of the bridge. Thence we pursue this bank of the river through the villages of Duncannon and Petersburg to the Juniata, along the southern side of which it is continued through Newport and Perrysville to a point a short distance above Lewistown. Here the line crosses to the north side of the river, and within a short distance recrosses, to save nearly a mile of road, and one hundred and eighty degrees of curvature, together with some difficult ground along the bluff shores on the south side of the stream.
After regaining the southern side we follow the river slopes, over favorable ground, to Mr. Harvey's, about seven miles above Waynesburg, where the line again crosses to the north side, and passing back of Newton Hamilton, cuts through the neck of land in the great bend of that stream, 40 feet in depth at the summit and 3,100 feet in length at grade. Descending along the eastern slope of the river, we once more cross it at Shaeffer's aqueduct, and continue upon its southwestern bank through Jack's narrows, without meeting any serious difficulties, and finally pass to its north side, along which it is continued through Huntingdon to the Little Juniata, above Petersburg. Above Huntingdon, a preliminary location has been carried up the Little Juniata to Logan's narrows, at which point this stream divides Bald Eagle and Brush mountains in its passage from Tuckahoe valley.
Along the Little Juniata, from Dorsey's forge to the Narrows, the line encounters much difficult ground, owing to the circuitous character of the stream, and the high hills and mountains which bound its course. To obtain a route with easy curves we are forced, within this distance, to tunnel the point of Tussey's mountain, and to cross the river twelve times. To follow the line recommended by Mr. Schlatter through this region curves of 400 feet radius would have had to be resorted to, which I deem wholly inadmissible upon a road of the importance of that you have in view.
At Logan's Narrows we reach the valley that skirts the whole eastern base of the Allegheny mountains. Here it becomes necessary to determine the plan to be adopted to overcome the great barrier that separates us from the West. If it is to be surmounted by a road, with the gradients of the western division, the ascent must commence at this point, and gradually wind its way to the summit, by an almost continuous gradient, along the declivities of the mountains for nearly thirty-two miles, crossing the several streams that issue from it, by high bridges, and cutting through or tunneling their dividing summits.
Mr. Schlatter, in his Report to the Canal Commissioners, estimates the cost of grading the road, on this ascent, at $1,496,146, which I consider too low for a line with the gradient he adopted, but with the increased maximum grade found necessary on the western division, and a somewhat lengthened line, it would probably prove sufficient.
Upon my first reconnoissance of this portion of the country it occurred to me that its peculiar topographical features were lost sight of in the adoption of this plan of ascent, which seemed to look to the single object of obtaining a line with a particular gradient, without regard to the magnitude of the obstacles to be overcome to procure it; while, by pursuing a course from the Narrows, nearly in a direct line to Sugar Run gap (which we shall hereafter show is the best point to cross the mountain), the line would pass through a beautiful valley over comparatively favorable ground, gradually gaining elevation through its whole course, without exceeding the maximum inclination required on the line below, until it reaches the summit of the valley at Robinson's, a distance of fifteen miles. At this point we attain an elevation of 1,174 feet above tide, leaving but 980 feet to be overcome to reach the height found most suitable for passing the mountain, which is attained by a continuous gradient of 80 feet per mile, encountering no _very_ formidable difficulties.
A resort to a gradient of 80 or more feet per mile is by no means an unusual expedient on leading railroads.
Upon the Western Railroad, in Massachusetts, their maximum gradient is 83½ feet per mile. On the Baltimore & Ohio Railroad they now have, between the waters of the Patapsco and Potomac, on each side of Parr's ridge, gradients of 82 feet per mile, and from the greater elevation of the Allegheny mountains at the place they must cross, it is to be presumed that their gradients at that point will still be increased to a higher rate.
Many other instances might be cited, some running up to 120 feet per mile, but it seems unnecessary to extend the list. Theoretically, the power necessary to overcome a given height is the same at all inclinations of the plane of ascent, but in practice, it is to some extent dependent upon the kind of power to be applied.
In the case under consideration, the locomotive steam engine will be the medium used, where the power is carried with the train, and forms part of the load to be moved, consequently, the cost of power on a plane ascending 80 feet per mile is greater than upon one of a more moderate inclination of equal height, by the difference between the gravity of the engines required to carry the same load on both planes.
As a general principle this would be true when the lengths of the roads to overcome the same height are equal, and it is necessary to carry the locomotives, required for the high gradient, over the same distance that they must run upon the low gradient.
But in one of these cases the maximum gradient due to the line below Logan's Narrows is carried to within 12¼ miles of the summit of the mountain--requiring extra power for that distance only--and in the other it ends 32 miles from it.
To explain more fully the relative value of the maximum gradients used on the different divisions of our Road, I have prepared the following table:
Table headings: Col A: Division of Road. Col B: Maximum Gradient, ascending westwardly, per mile. Col C: Maximum Gradient, ascending eastwardly, per mile. Col D: Gross load of a 20 ton freight locomotive, exclusive of engine, and a tender of 10 tons. Friction 8½ lbs. per T. Adhesion ½. Col E: Load of merchandise for a 20 ton freight engine, the cars being estimated at 4/10ths of their weight and load. Col F: Relative load of locomotive on each gradient, level being unit. Col G: Number of locomotives of equal power necessary to carry the same load up each gradient.
====================+========+========+=======+=======+=======+===== A | B | C | D | E | F | G --------------------+--------+--------+-------+-------+-------+----- From Harrisburg | { 16 | | 346.6 | 207.9 | 0.534 | 1.87 to Lewistown, | { | | | | | 60-7/10 miles | { | 8 | 454.3 | 272.6 | 0.697 | 1.42 --------------------+--------+--------+-------+-------+-------+----- From Lewistown | { | | | | | to foot of | { 21 | | 300.7 | 180.4 | 0.464 | 2.15 Allegheny Mts., | { | 10½ | 414.6 | 248.8 | 0.640 | 1.56 72 miles | { | | | | | --------------------+--------+--------+-------+-------+-------+----- From foot to summit | { | | | | | of Allegheny | { 80 | | 105.6 | 63.4 | 0.163 | 6.13 Mountains, | { | Level | 648.0 | 388.8 | 1.000 | 1.00 12-3/10 miles | { | | | | | --------------------+--------+--------|-------+-------+-------+----- From summit to | { 47 | | 172.4 | 103.4 | 0.266 | 3.76 Pittsburg, 106 | { 50 | 50 | 163.7 | 98.2 | 0.252 | 3.95 miles | { 52.8 | 52.8 | 156.2 | 93.7 | 0.241 | 4.14 --------------------+--------+----------------+-------+-------------
It will be perceived from the foregoing table that three locomotives are fully sufficient to transport the same load up the 80 feet gradient that two will carry on the gradient of the western division, and one on the eastern; hence the practical working of the road on the two methods of ascent would be to run two locomotives with the load brought from below from Logan's Narrows to the summit, say 31¾ miles, up the 50 feet gradient; while, on the other, the same engine that brought the load from Harrisburg would continue with it to Robinson's (15 miles), where it would accompany the two destined for Pittsburg to the summit of the mountain and return.
In the first case the engines together will have traveled 63½ miles, and, in the other, the three 51¾, leaving a difference in distance to be traveled by the moving power due to each full train, from the east, 11¾ miles in favor of the 80 feet gradient.
In practice it will therefore be seen--chiefly on account of the actual distance saved--that transportation can be afforded cheaper, in this case, on the 80 feet gradient than on the 50, without bringing into the estimate the interest on $841,000 that the latter would cost to obtain it more than the former. Under these circumstances we did not hesitate when the choice of routes was reduced to a selection between these two methods of overcoming the mountain, to decide in favor of the line by Robinson's, which has the additional advantage of bringing us within 6-1/3 miles of Hollidaysburg, where a connection may be made with the Allegheny Portage by a branch line, passing over favorable ground.
The distance from Harrisburg to Robinson's summit is 132-2/3 miles; upon the whole of this line, the only extraordinary impediments to the easy graduation of the road bed are the bridge over the Susquehanna, a deep and long cut near Newton Hamilton, and a tunnel 1,200 feet in length through a point of Tussey's mountain, and in this distance the maximum ascending gradient to Lewistown is 16 feet per mile, and descending 8 feet. Thence, to Robinson's summit, they are increased to 21 feet ascending, and 10-1/8 feet descending.
The descending gradients are generally so short that they will not be found, in practice, to decrease the load going east much below what is due to a fair _working_ load for a locomotive on a level.
The maximum ascending gradient above Lewistown is determined by the deep cut near Newton Hamilton. The ascent of the Little Juniata seems, however, to require--to obtain an economical line--the use of this inclination, without much intermission, from Dorsey's forge to Robinson's summit. Below Lewistown the gradients are fixed to accommodate the increased trade that would fall upon the line between that place and Harrisburg, without increasing the number of trains.
These low gradients insure to us the important advantages of a single pair of drivers for the passenger engines, upon the eastern division, and, with these rates of inclination, we are enabled to make the line conform to the natural features of the country (above high water mark) without decreasing the curvature below 955 feet radius, except at the east end of the Susquehanna bridge, where a radius of 880 feet has been admitted.
All of our efforts to save distance, by deviating, temporarily, from the immediate valley of the river, involved either the use of high gradients, not justified by the distance saved, or an increased cost that was equally unwarranted. The beautiful valley of the Kishacoquillas offered the greatest temptation to leave the river route; but here we would have had to encounter gradients, in both directions, of 26-4/10 feet per mile, a bridge over Mill creek, 1,200 feet long, 111 high; another over a small tributary of the Juniata, 850 feet long and 150 feet in height, together with several others, or embankments of great magnitude, across ravines in the north slope of the river hills. These difficulties, added to 342 feet of additional elevation to be surmounted at the Allentown summit, so greatly overbalanced the small increase of curvature and distance (7/10 of a mile), by the river route, that it could not be adopted. It was also ascertained that by the _use of the maximum gradients_ required on the valley route, the shortest line could have been procured by the river, and at the least cost. A fact, conclusive in itself, as to the proper route.
I deemed it unnecessary to make further instrumental examinations of the Stone mountain route, feeling satisfied that even if a line could be obtained in that direction which would approximate to an equality, in an engineering point of view, with the route selected--which, from a reconnoissance of a portion of the line and an examination of the plots of Mr. Schlatter's surveys, I should consider _quite_ improbable--that its additional cost would entrench so much upon the means of the Company as to place it entirely out of the question.
A line was traced from Huntingdon to the Frankstown branch of the Juniata, below Williamsburg, across Tussey's mountain, by which a saving of distance could have been made nearly equal to the Stone mountain route, but its high gradients, cost, and the length of time that it would require to build the road over it rendered it equally objectionable. The valley of the Frankstown branch was also surveyed; the route by it joining the Little Juniata line at Robinson's ridge, but it proved both longer and more expensive than the latter. The searching examinations made of the whole region offering any chance for a more practicable route, on the north or south of the Juniata, leaves no doubt upon my mind but that the best line has been procured for the eastern division. Its comparatively easy curvature and low gradients, adapted in their inclination to the direction of the largest business, and extending from the eastern terminus of our Road to the foot of the great barrier that divides us from the west, give it advantages that are not equaled by any other route proposed, between the east and west, and can not be too highly appreciated by the Company.
Before determining the point to pass the mountain, a full examination of its crest was made, from Cedar Swamp summit on the south, to Three Springs Gap at the head of Moshannon creek on the north, embracing a distance of 44 miles. The following table will show the elevation, above tide, of each summit within that distance; also, that at Emigh's Gap, on the northern route, and at the head waters of Castleman's river on the southern:
_Tabular Statement of Depressions of Allegheny Mountain._
===================+=============================+================ | | Name. | Waters Divided. | Authority. | | -------------------+-----------------------------+---------------- Summit of Chesa. & | | Ohio Canal | Castleman's and Potomac | U. S. Engineers Albright's Summit | do. do. | Sand Patch do. | do. do. | J. Knight Chambersburg and | | Pittsburg Survey | | H. Hage Cedar Swamp Gap | Raystown Branch of Juniata | | and S. Fork of Conemaugh | S. H. Long Bob's Creek do. | Raystown B. and Conemaugh | do. Big Spring do. | Juniata and Conemaugh | do. Laurel do. | do. do. | do. Adams do. | do. do. | do. Portage and Summit | Juniata and Clearfield | C. L. Schlatter Sugar Run Gap | | S. H. Long Burgoon's do. | do. do. | C. L. Schlatter Kittanning do. | do. do. | do. Dry do. | do. do. | do. Hamer's do. |Little Juniata and Clearfield| do. Schultz do. | do. do. | E. Miller Cock Run do. | do. do. | do. Maple do. | do. do. | do. Bell's do. | do. do. | do. Three Springs Gap | Little Juniata and Moshannon| do. Emigh's do. | do. do. | C. L. Schlatter -------------------+-----------------------------+----------------