6, and commenced the cuts at its extremities winter set in before the headings were started, and the work had to be abandoned.

The year before, some gangs had been sent to summit tunnel No. During the fall of that year the track reached Cisco, and as fast as the gangs of Chinamen were released they were hurried to the summit to be distributed among the tunnels in its vicinity.

Tunnels 1 and 2 are both west of Cisco, a small track 92 miles from Sacramento, and within 13 of the summit. It is within these two miles that seventunnels are crowded. Another important object was the savingof snow-covering where tunnels were made, and giving a good foundationfor it where they were not. On these accounts the line, for twomiles east of Donner Pass, was thrown further into the hill than on originallocation, thus adding to the depths of cuttings and increasing the numberof tunnels, but saving retaining walls, and where tunnels were made, enablingthe work to be carried on in winter.

In such places embankments were almost impracticable the hills weretoo steep to catch the slopes, and most of the rock from cuts was thrownfar down hill by heavy seam blasts. The line here lies on steep hillsides, in some cases being,for long distances, on a face of bare granite, more or less broken by projectingledges and boulders, but with an average slope often greater than 1 to1. The tunnels of the Central Pacificare nearly all near the summit, where it crosses the western range of theSierra Nevada. Four of theseare on the Union Pacific and fifteen on the Central.Ĭentral Pacific Tunnels. Some account of a single item in the greatwork may therefore be interesting.īetween Omaha and Sacramento there are nineteen tunnels. GILLISS, Civil Engineer, Member of the Society.ĭuring the past summer the track has been completed across this continent,and so much sooner than was thought possible, that the difficulties overcomeare apt to be underrated. CourtesyDan Austin.Ībstract of a Paper read before the American Society of Engineers, Jan.5, 1870, by JOHN R.

Van Nostrand's Eclectic Engineering Magazine, Vol. Use of this Web site constitutes acceptance of the User Agreement which permits personal use web viewing only no copying arbitration no warranty. Tunnels on the Pacific Railroad Central Pacific Railroad PhotographicHistory Museum

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