Utah Central Railroad (1897-1908)

THE RECONSTRUCTION OF THE UTAH CENTRAL RAILWAY.

By W. P. Hardesty, C. E.

The old Utah Central Railway was .a narrow-gage line, connecting Salt Lake City with Park City, and was 33 miles long. Park City is a rich mining camp on the east side of the Wasatch range of mountains. It is reached by a branch of the Union Pacific Ry., running from Echo, on the main line, in a southerly direction up the valley of the Weber River, and thus securing a comparatively easy grade. But to reach Park City by a direct line from Salt Lake City, the Wasatch Range must be crossed. This is done by this road by following up the canon of Parley's Creek to the divide, and thence descending the east side to the valley, near the head of which is located Park City.

The narrow-gage line was built about 20 years ago. It has proven an exceeding difficult and expensive line to operate, the projectors seeming to place but little value on a road built for economical operation. Besides the excessive grades, there has always been much expense in contending with the deep snows every winter. It was never a profitable line, and in 1893 went into the hands of a receiver. Finally, early in 1898, it was purchased by the Rio Grande Western Ry. Steps were at once taken for its improvement. The new ownership gave it traffic connections that it entirely lacked before, and it soon began to make earnings that seemed to justify changing it to a standard-gage line, with all the radical alterations needed for a line with considerable traffic. Careful surveys were made, and in December, 1899, work was begun on the change of line here described. The new line extends from Barclay (about 16-1/2 miles from Salt Lake City) on the west slope to Gogorsa at the foot of the east slope. The distance between these two stations by the old line is 6-1/2 miles. An inspection of the profile of the old line will show why it was necessary to lengthen out the new one. Beginning at Barclay, there are no grades going up to the summit of less than 3-1/2%, ranging from that up to 6-1/4%, while grades of 5% to 6% are very common. There is a climb of 813 ft. in the three miles to the summit, or an average of 271 ft. to the mile. On the east side the grade varies from about 2-1/2% to 4-1/4%, there being 667 ft. fall in the 3-1/2 miles, or an average of 191 ft. per mile. Many of these heavy grades also came on sharp curves. The maximum curvature on the line was 20°. There were also three switchbacks on the west slope.

On the new line, the maximum grade is 4% on the west slope and 2.7% on the east one, compensated for curvature at the rate of .045 per degree. The maximum grade is continuous on the east side and nearly so on the west one. The maximum curvature is 16°, and there are many of this and of 14°. Considerable development is required on both sides to gain distance, and thus secure the reduced grade. There is much heavy rockwork on the west side, the material being used to make the adjoining high fills. On the east side most of the line is in fill, much borrowing being required. Fills are used on account of the great trouble on this side that was experienced with snow by the old line. The west slope is more exposed to the sun, though the snow becomes quite deep here, too. Probably 80% of the entire excavation was in solid or loose rock. There are 15 through cuts, the longest being 700 ft., and the average length 500 ft. There are 15 fills, the longest also being 700 ft., and the average 500 ft. The deepest cut in 55 ft., and the average 35 ft. The highest fill In 70 ft., and the average 83 ft. The old line is crossed once on the west side and three times on the east side, at grade.

SUMMIT TUNNEL.

The summit of the divide is about 19-1/2 miles from Salt Lake City. The old line went over the summit at a grade elevation of 7,048 ft. above sea level. The new road is tunneled through the divide by a tunnel 1,116 ft. long. The summit of the grade is just beyond the east portal of the tunnel, 106 ft. lower than the old summit, and nearly 123 ft. lower than the natural summit of the divide. As shown by the map, the old line made a horseshoe curve in going over the summit. The new line goes through it on a tangent, crossing under the old one near each portal. The divide or saddle here is not a solid formation, but seems to have been made by a slip from the adjoining mountains. Consequently, it is much faulted, and the ground is soft and loose. It is mostly shale or talc, with a little limestone-slippery and mean.

The superintendent of construction of the tunnel was Mr. C. E. Higbee, who has had an extensive experience on railroad tunnel work, having built, among others, the Tennessee Pass Tunnel for the Denver & Rio Grande, in Colorado, and also the tunnels on the Tintic Range Branch of the Rio Grande Western, in Utah. Work on the approaches was begun about the first of December, 1899; on the headings about Jan. 1, 1900. The headings met the latter part of April, and the tunnel excavation was finished on June 1.

The tunnel is timbered throughout. The approach cuts are about 55 ft. deep at each portal. On account of the loose ground, the two or three sets of timbers at each portal had to be strongly braced to take the outward pressure, and breast boards were also built on top of the portals to catch the sliding material. The regular excavation is 18 ft. wide by 24 ft. high, the clear space inside of the timbers being intended as 16 by 22 ft. The sets of timbers are 4 ft. apart, center to center. They are of 12 x 12 timbers; plumb posts 15 ft. long; arch of 6 segments and built to an 8-ft. radius; that 18, 8 ft. high and 16 ft. wide. Lagging is of 8-in. plank, 4 ft. long. There are also cross braces between opposite mud-sills at the bottom.

The headings of the tunnel were over half through when excavation of bench and timbering began in March. All drilling was -by hand, but as the ground was soft this was a small part of the work, requiring only 4 men. Work was carried on in two shifts of 10 hours each. A full force on the bench excavation and timbering consisted of 18 to 26 men. Of these, 6 men would be engaged in cutting out the sides for and placing the timbers. These men were assisted by the muckers when the plumb posts were to be raised. Pulleys were used in raising these and the other timbers. The bench was excavated by two "lifts," working at the same time, the upper one by wheelbarrow and runway, the lower one by shoveling direct into the cars. The excavated material was hauled out in side-dumping cars, and used in neighboring fills or else wasted. The material seemed to increase or swell greatly on exposure and breaking, and it is claimed that one cubic yard of excavation must sometimes have made two or three cubic yards in the dump.

About 700 ft. of the tunnel was run from the west end. The air became foul in the west heading after getting in 400 or 500 ft. (there being no provision for supplying air), so after this, work was not pushed on this end so fast. It was better than the east end to work in other respects, having good drainage and a down grade for the dump-cars. At the east end it was necessary to pump the water out. The flow of water was much reduced after running for a few weeks after being tapped by the tunnel. The greatest progress made at either end was 8 ft. in one shift. The average was 9 ft. in two shifts. Owing to constant changes being made in the employees, it was difficult to keep a force up to the standard fn size or efficiency for the tunnel excavation and timbering. All told, there were about 100 men employed in connection with the tunnel work during active construction.

Much trouble has been had with the soft and yielding ground. Beginning at the east end, the timbers on the south side gradually sank from 1/2 to 2 ft. for over 260 ft. in. There is a bad fissure or slip in the ground on this side, which the line of posts seemed to closely follow. It leaves the tunnel near the end of this section. The timber bents were, of course, badly distorted, and to strengthen them additional alternate ones were put in between the others. The joints of the segments of the arch were also cleated on each side. The great pressure in places partly crushed the wall plates and split the plumb posts. The settlement was caused by the poor foundation afforded by the loose and wet ground. Cross timbers were placed between the posts of each bent near their tops, to take up the great inward pressure. On taking out two or three of these to give sufficient clearance to work trains, at the end of the bad ground, a cave-in resulted which took considerable time and labor to repair and backfill.

It was decided to build concrete walls where the ground gave trouble. This was done by the railway company soon after completion of the tunnel by the contractors, Mr. Higbee being retained as superintendent for it. About 600 linear ft. of wall was built, all but about 100 ft. of it on the south side. Near the center of the tunnel about 100 ft on each side was concreted. The settlement developed here after that of the 260 ft. before mentioned. Beyond the cave-in the ground stood firmly for some distance in.

The concrete was composed of Utah Portland cement, sand and broken slag in proportions of 1, 2 and 6. It was mixed on flat cars just outside the tunnel and then run in and used. The walls of concrete were made about 4 ft. thick and 17 ft. high. Where there were two, they were started about 14 ft. 6 ins. apart at the bottom and battered back until about 16 ft. apart in the clear at the wall plates. The lagging was taken from behind the posts, and the material then excavated for the desired thickness. It was put in in two lifts, the first one directly from the cars, the upper one from a scaffold. The excavation back of each post was first made; at the back of this an 8 x 8-in. post was set, and a short cap run from it to a support on the main post. A plank covering was put on these to catch the falling ground from above, and the excavation for the lift then completed. The posts were concreted fn. It took about two cubic yards of concrete per linear ft. of wall. If the original 16 ft. clearance between sides had not been lessened by the loose and wet ground forcing them in, the posts would be completely hidden by the concrete. The ground was excavated for 8 or 4 ft. inward in front of the mud-sills, and 14 ins. of concrete put in, coming 2 ins. over the sills. At the top the concrete was brought 1 ft. over the top of the wall plates, the lower end of the first segment of arch being thus concreted in. It was found here that the joint this segment made with the wall plate was one of the weak points of construction, the pressure inward tending to flatten the joint or angle, already too light on account of the slight angle at which the segment stands from the vertical. The pressure at the wall plate did not develop until after the timbers were placed and it was, of course, hard to anticipate in advance just what form of arch would be best suited. Mr. Higbee considers the 6-segment arch poorly suited for the character of ground found here, the angles at the joints being too fiat to stand much pressure inward unless the same be evenly distributed. He thinks that, though looking much better than others, that when the pressure is uneven and heavy, tending to distort the arch, that this form should be displaced by the 8-segment arch. For the pressure usually found in tunnels (mostly vertical), the 6-segment arch is undoubtedly the best and strongest.

The wooden arch will rot in time, and will then have to be replaced with new timber or by a masonry arch. The concreting was done after regular trains had begun to run through the tunnel, between trains. The scaffold used for the upper lift of concrete was a swinging one, being hinged or hooked on to straps nailed on to the posts. The outer edge (it being 3 or 4 ft. wide) was supported by diagonal braces reaching down to the lower parts of the posts. When a train was to be let through, the braces were taken out and the scaffold swung down next to the posts.

The slag used in the concrete was hauled from the smelters near Salt Lake City, and was made use of notwithstanding the long haul on account of the difficulty of obtaining sound, hard stone from the rock excavations on the line. Its use was cheaper than opening up a quarry nearby and hauling by wagons. It was broken up by band, though not so fine as customarily.

TRESTLES.

There are some trestles on the line with unusual features. On the south side of the great loop north of Barclay is a high fill across a large gulch. As material was lacking to carry this fill up to the grade of the track, even alter considerable borrowing, a trestle is used on top of the fill. This trestle has 16 spans of 16 ft. each. The bents gradually increase in height from the adjoining completed fill out, the 10 middle ones being of a uniform height of about 17 ft. to the grade of the track. To fill to grade here would require a fill about 70 ft. high at the center and 100 ft. high from the toe of the lower slope. The fill contains a large percentage of broken rock. The bents are founded on the fill as follows: Under each batter post are placed four pieces of 8 x 12-in planks, x 5 ft. long; crossways of this are placed two pieces of 6 x 8-fn. timbers 4 ft. long. Under the two plumb posts are first placed four .pieces of 3 x 12-in. planks 12 ft. long; and upon this are placed two 6 x 8-in. timbers 4 ft. long. On these foundations is then placed the regular 12 x 12-fn. sill, running at right angles to the short sills next below them. The foundations have sides of plank nailed to them, running parallel with the bent, to keep adjoining material from running fn on them when they settle. It was found that this fill settled 2 ft. before trains were run over the trestle, and the trestle bents have been gradually settling since then. The settlement is taken up by placing additional pieces of timber under the short cross-sills, the bents being first jacked up to grade.

About 1/2 mile above Barclay the line leaves the south side of the canon and crosses over to the west side, doubling back down the canon. The deepest part of the canon is crossed by a trestle of 16 spans, 248 ft. long. This trestle is on a 16° curve. At the end of the approach fill on the west side it is sloped down gradually, so that four or five of the shorter bents are founded on filled material fn the same manner as for the other trestle. The track is 65 ft. above the bed of the creek below, requiring a three-deck trestle here.

The highest trestle is at the crossing of Lamb's Fork, the largest branch of the main creek. This was built to replace a switchback on the old line before the main change in the lines was began, and it is just below Barclay. It is a 19-span trestle about 300 ft. long, and is on a 16° curve. The track is 82 ft. above the creek below. This trestle is one of the scenic features of the line. The switchback referred to ran up Lamb's Fork for nearly 1/4-mile. Considerable time was lost thereby in running the trains, while no elevation was gained.

As said before, the operating of the old line was exceedingly expensive. The heavier trainloads, consisting mainly of ore from the mines at Park City, are moved westward, for which reason it was necessary to have lighter grades on the east side. The most powerful engine on the narrow-gage was one with 60,000 lbs. on eight 30-in. drivers, with a total weight of engine and tender of 116,000 lbs., and 16 x 20-in. cylinders. There were other engines with a total weight of 129,000 lbs., but only 55,000 lbs. on the drivers. Three loaded cars (weighing 20 to 25 tons each) were all that one engine could pull up the east side, and about two on the west side.

The locomotives now used are the consolidation engines. with 108,000 lbs. on the drivers, and a total weight of about 195,000 lbs. Up the 2.7% grade on the east side, one of these engines can pull 8 or 9 loaded box cars (weighing 90,000 to 95,000 lbs. each), and up the 4% grade on the west side about 5 cars.

The track is laid with 65-lb. rails, except for about 15 miles of the lighter grade, where the 40lb. rails have not yet (Sept. 1900) been replaced. The 40-lb. rails cannot carry the latest large engines of the Rio Grande Western road (illustrated in Engineering News of Aug. 30 last), which have 169,000 lbs. on the drivers and a total weight of 295,000 lbs. Even the 190,000-lb. engines have to run slowly over the track where these rails are laid.

In addition to the radical change of line and the standard-gaging, there have been changes at other points, where bad curves have been straightened out. Most of this was done in the main canon, where the road lies near the bottom. The construction work has been done by the Utah Construction Co., of Ogden, which had an average of 500 men at work for several months. The main contract was completed early in June. Mr. Samuel J. Norris was the Engineer in direct charge of location and construction. He was immediately under Resident Engineer F. E. Baxter, who has had an extensive experience on location and construction of railways in the West. All the work was under the supervision of Mr. E. J. Yard, the chief engineer of the Rio Grande Western Ry.

The entire cost of the change and standard-gaging has been nearly $400,000. Regular trains began running over the standard-gage line about the last of July.