Before lining all of the bore, vertical shafts were excavated to the ground surface for the purpose of providing air ducts to surface installations for forced ventilation facilities for the entire tunnel. These installations are concrete lined and the fan houses are of monolithic concrete construction. The ventilating equipment is installed so as to be actuated by traffic through the tunnel. Throughout the open cut sections of the tunnel, the outside of the tunnel barrel was coated with hot asphalt, and 4-ply cotton membrane waterproofing material was applied. After applying a coat of hot asphalt to this material, 1-1/2-inch asphalt plank was applied and compacted earth backfill was placed in depths ranging upward to 4 feet above the tunnel barrel. The waterproofing was extended to elevations above the operating levels of the reservoir. The method of placing concrete in the railroad tunnel was as follows. The mixed concrete was hauled from the central batching plant in mobile transit mixers mounted on end-dump trucks, to where an 8-inch double pumpcrete machine was set up at the end of a ramp. The pumpcrete machine pumped the concrete through two 8-inch lines, one to each side of the barrel. A fairly steep slope was maintained in the concrete in order not to open up too much area at one time. Four 2-1/2-inch-diameter head electric vibrators were used on each side, and the concrete was placed alternately on one side and then the other. A "slick pipe" was used on the end of the pumpcrete line for sealing the crown section of the tunnel. This pipe would be left in the concrete for a few feet in order to build up pressure to force the concrete into all openings possible. White pigmented curing compound was used throughout the construction of the tunnel for concrete curing and proved fairly satisfactory. Additional information on concreting procedures is given in chapter XXII. 123. Open Trackage. A protective feature, included at all locations where the railroad embankment might be subjected to inundation from the reservoir, was to enlarge the embankment cross section to include a 10-foot-wide berm well above the normal operating levels of the reservoir. The slope up to the berm was covered with a 3-footthick blanket of riprap. All track materials used on the relocation of the main line were new and conformed to standards of the American Railway Association. The materials were furnished by the Government, with title to abandoned facilities reverting to the Bureau of Reclamation subject to reservations imposed by the railroad company. The ballast furnished for the track was of excellent quality crushed and graded stone meeting the specifications. Its gradation and irregular cleavage resulted in a ballast section inclined to become stable rather slowly; consequently progressive settlement may continue for several years. The ballasting, tracklaying, and work incidental to the completion of the trackage was subcontracted. This included the delivery of track materials and ballast from railroad cars or other sources to the point of utilization. Ninety-pound rail, creosotetreated 7- by 9-inch fir cross ties, and appropriate fittings were used on all exterior trackage. In the tunnel section 129-pound rail, in 975-foot lengths fused from shorter rail lengths were placed on 7- by 9-inch cresoted oak cross ties. The ties, rails, and other track building materials were distributed along the shoulder of the finished subgrade of the roadbed except within the tunnel where other practices were required. Following the distribution of the track materials, ballast which was produced and processed by the prime contractor was hauled and dumped on the subgrade with trucks. The ballast as placed in this manner was initially intended to form the required ballast section of the completed roadway. A crawler-type tractor with a dozer attached was used to level the piled ballast. The resulting ballast course was uneven and varied considerably in depth, being generally shallower than the 12 inches required under the cross ties. Ballast was not placed between the cross ties and the rails were not placed accurately to grade and alinement. Long reaches of trackage were built in this manner and were subject to the influences of the wide variations of temperature which occur in this area during the year. The cumulative effects of these construction practices and temperature variation resulted in additional work during the final track raising and surfacing operations. Many ties required alining and respacing, rail joint tolerances varied considerably from the required standards, and the trackage alinement irregularities were adversely affected by stresses induced by temperature changes. In one extreme case, temperature-induced stresses in the rail forced the formation of a kink in the track which required the removal of several feet of rail to allow the necessary alinement corrections. During the final ballast dressing operations, the subcontractor applied additional ballast, which was hauled in track cars from stockpiles located at accessible points along the track. The subcontractor had an experienced and efficient track building gang of about 25 men. All of the work of track building and surfacing was done without the aid of a crane or pneumatic equipment. One piece of mobile equipment, which proved useful in the completion of the ballast dressing, was an adequately powered, adjustable automotive unit mounted on a heavy track car. This piece of equipment channeled the excess ballast from the edges of the section toward the ends of the cross ties to form a well-dressed and uniform slope line. Other attachments brushed the ballast from the surface of the ties to complete the dressing operations. Tracklaying operations in the tunnel were complicated by restricted space. Used 90-pound rail, which was ultimately to serve as guard rail, and the ties were hauled into the tunnel in trucks after a 4-inch course of ballast was placed on the concrete invert. The ties were then placed and the 90-pound rail laid to permit its temporary use by a worktrain, which transported and distributed the 129-pound rail. The rails were unloaded by drawing the train from under the 975-foot lengths of rail. Track crews then installed the heavier rail and moved the used 90-pound rail into its final position to serve as guard rail. The new rail was thoroughly coated with a rust-resisting compound. Insulated rail joints in and beyond the tunnel were installed to actuate traffic signals and ventilating equipment in the tunnel by train traffic. The remaining ballast, obtained from the railroad company's quarry near Gurnsey, Wyo., was brought in and distributed from work train equipment. This ballast was crushed, graded rock, nearly free from material passing the No. 4 screen, but having smooth angular cleavage planes conducive to the formation of a stable ballast section. The Government furnished the materials for the construction of the telegraph line and the right-of-way fencing. The prime contractor negotiated subcontracts with individuals for erection of the telegraph line and the fencing. The subcontractors furnished little more than the labor and supervision incidental to erection of these facilities. These installations were generally replacements of abandoned facilities with new materials. Steel fence posts were used instead of concrete fence posts in the right-of-way fencing except for intermediate and terminal bracing, where reinforced concrete assemblies were installed. Relocation and elevation of the trackage below Boysen Dam required that housing and water facilities, about a mile below the dam, be relocated. A suspension foot bridge, spanning the river channel, was built to provide access from the relocated section house to highway facilities. The suspension foot bridge replaced a cable car installation which existed near the original section house location. A feature of the contract agreement with the railroad company, provides for a deferred maintenance contract whereby the Government is to reimburse the company for maintenance costs, in an amount not to exceed $600, 000, incurred by forces designated by the company to repair and maintain its relocated facilities and installations for a 5year period following the date when the water surface elevation of the reservoir first reaches its normal operating level. The effective life of the contract will extend beyond calendar year 1957. In relocating the railroad around the reservoir and by the dam, the Government bore the entire cost of all materials and personnel services, including all expense incurred by the railroad company in the process of initiating and conducting activities relating to the relocation. In accordance with the usual custom, railroad forces performed the necessary work required to adapt the portions of trackage, existing at each end of the relocation and being subjected to normal traffic, to the elevation and alinement requirements necessary to effectively connect with the relocated installations at the time of completion. The relocated facilities were placed in service when the railroad company tentatively accepted this work during September 1950. 124. Salvage of Materials. The abandoned rail facilities were dismantled and usable materials salvaged during the last half of the year 1951. The subcontractor removed and stockpiled the track materials. This contractor was well equipped and seemingly experienced in such salvage work. The prime contractor's forces salvaged the steel girders and useful timber from the several abandoned bridges. Government forces salvaged the telegraph lines and right-of-way fences which were abandoned. Early the following year local interests were awarded a contract permitting them to remove castiron culvert pipe from the abandoned roadway and convert the material to their use. Some quantities of rail and related metal fittings were used for the building of passing tracks, sidings, and guard rail in the Chicago, Burlington and Quincy Railroad relocation schedule. Track materials, including the more serviceable cross ties, were salvaged and used in the construction of the relocation of the Chicago and North Western Railway. Telegraph line materials were likewise converted in quantity to use in the communication line work which was a part of the Chicago and North Western Railway relocation. Remaining track materials, except cross ties, and steel bridge girders reverted to the railroad company according to the contract-agreement. Quantities of cross ties, telegraph poles, and other materials were disposed of through routine processes. 125. Difficulties in Construction. - Inadequate ventilating equipment used by the contractor in the tunnel during operations with diesel-powered mucking machines and trucks, caused some sickness to employees as well as to some of the Government inspection forces. Some difficulty was also experienced with pumpcrete machines breaking down and in some instances causing cold joints. A slide at the south portal occurred on March 2, 1949, which crushed the steel supports already in place. A revised portal was designed to resist further movement of the rock and was successfully placed. In all, about 20 feet of the tunnel was lost. After the completion of the concrete lining in the tunnel all possible voids were backfill grouted. Considerable leakage has continued in that part of the tunnel which is below, or partly below the high water level of the reservoir, in spite of several efforts by the Government as well as company railroad forces to high-pressure grout these areas. CHAPTER XVI--RELOCATION OF THE CHICAGO AND NORTH WESTERN RAILWAY 126. General. Relocation of approximately 3.4 miles of the Chicago and North Western Railway's trackage near the upper end of Boysen Reservoir site (figs. 53 and 54) was prompted by the need to remove this portion of the trackage from the reservoir area to be inundated. Negotiations between the Government and the railway company resulted in an agreement whereby the company was to bear the cost and perform the work necessary to build a new 35-span pile bridge across Muskrat Creek, do necessary grading and channel protection at the bridge, and relocate about 1, 200 feet of trackage and related facilities beyond Muskrat Creek. The contract agreement further provided that the Government would furnish the ballast and second-hand ties for the trackage beyond Muskrat Creek and second-hand 90-pound rail, joint bars, tie plates, and the right of way for the entire bridge and the portion of the trackage beyond the bridge. 127. Roadbed. The embankment and roadway construction for the relocation was delayed until late in October 1951 when the culvert pipe was received by the contractor. Bituminous-coated, zinc-plated corrugated-metal pipe, pipe arches, and multiplate culverts ranging in size from 24-inch diameter to 120-inch diameter, were used for all cross drainage structures, except the Muskrat bridge which was raised and relocated by the railway company. All the culverts were installed during October and November 1951; however, backfilling around these structures was not completed until the following spring. The contractor opened up excavation over the full length of the relocation late in 1951 and moved approximately 13, 000 cubic yards of material before cold weather forced shutdown for the winter months. The majority of embankment construction during this period was confined to that portion of the roadway beginning at Muskrat Creek and extending northward about 1 mile. Grading work was performed by tractor units which powered self-loading scrapers. The majority of the embankment material was placed in a dry condition requiring rolling. The double-unit 60-inch drum roller, operated without ballast, tended to spread the embankment and resulted in excessive roadway width. The contractor resumed work the latter part of March 1952 when two new, rubber-mounted, earth moving units were placed in service. These units replaced the tractor-drawn scrapers used previously and proved to be extremely adaptable and well suited to long hauls. Excavation and placement of fill was scheduled to allow the completion of the subgrade to progress northward from the Muskrat Creek bridge. The subcontractor began delivery of track materials and placed a 3-inch ballast course as the subgrade thereby permitting track work while earthwork was progressing northward. Wide variation of materials encountered in grading operations made it necessary to use explosives in limited areas and a heavy tractor-drawn ripper in all roadway cuts where sandstone, shale, or siltstone were encountered. Alluvial soils, prevalent along the southern half of the relocation, were composed of fine sands containing a high percentage of silt. In the area immediately north of Muskrat Creek, silt containing considerable organic matter overlaid a tight, heavy, clay formation. In construction of the northern half of the relocation the contractor was directed to borrow over 6,000 cubic yards of selected material for base construction of fills ranging from 3 to 15 feet in height. Excavated material not suitable for embankment construction was used to build dikes to protect roadway cuts from surface drainage, to widen certain sections of roadway embankment, or was wasted. Sandstone and shales encountered in roadway cuts proved to be satisfactory embankment material when mixed, moistened, and rolled in layers of 2-foot thickness. The subgrade was surfaced with a 1-foot layer of material suitable for fine grading. 128. Ballast and Tracklaying. Track materials furnished by the Government were hauled to the job site by truck and unloaded and distributed along the shoulders of the subgrade in conformity with requirements. The prime contractor produced approximately 7,000 cubic yards of ballast with a mobile crushing and screening plant. The specifications for ballast grading required that 100 percent pass the 1-1/2-inch standard screen, and permitted 20 to 50 percent to pass the No. 4 standard screen. The ballast as produced contained a low percentage of |