The Big Bore: Conquering the Sierra |

The Big Bore: Conquering the Sierra

Photo by Mark McLaughlin Donner Lake and the original Central Pacific railroad track. It took 12,000 men to blast tunnels through the Sierra Nevada granite.

In order to conquer the storm-wracked Sierra Nevada crest, the most challenging section of America’s first transcontinental railroad, Central Pacific hired thousands of Chinese laborers to dig and blast their way through the obdurate granite. The Chinese immigrants were sometimes called “Celestials” because they referred to their native land as the Celestial Kingdom. Contracted from China specifically to build Central Pacific’s railroad, the men were paid $30 to $35 per month. During the winter of 1866-67, construction workers endured 44 storms that dumped nearly 45 feet of snow on the range, and unleashed a swarm of deadly avalanches upon the workmen. Despite the formidable obstacles of ice and granite, rail by rail, the hard-working Chinese crews slowly pushed the track east, reaching Donner Summit on Nov. 30, 1867. Engineering and constructing a railroad through the Sierra Nevada had long been considered an impossible folly. William Tecumseh Sherman, who later became a Union General in the Civil War, was an experienced engineer and surveyor familiar with the Sierra Nevada. He wrote his brother of the project: “If it is ever built, it will be the work of giants.” Even Horace Greeley, editor of the New York Tribune and ardent advocate of westward migration who exhorted “Go west young man!” came to the same conclusion: “It is perfect insanity, or the next step to it, for any one to indulge in further discussion about the feasibility of a railroad from the Mississippi to the Pacific Coast at the present time [1848]. He added, “If Congress had common sense, they would not discuss such a subject … but those men in Washington seem to be more disposed to make fools of themselves, at the price of $8 per day to the people, than go to work and do their duty to their constituents.”

Theodore Judah and 12,000 ChineseIt took young Theodore Judah, a brilliant engineer from New York, and an army of 12,000 diminutive Chinese workers to prove the skeptics wrong. China had built the Great Wall, now her people would accomplish another tremendous feat of construction. Judah was able to convince the U. S. Congress that he could snake a railroad through the treacherous California Mountains, but despite his savvy business acumen and engineering expertise, he had no real understanding of the great danger, power, and frequency of snowslides in this region. In the Sierra high country, the track was built along avalanche-prone, steep-sided slopes. Sometimes the railroad clung to bare granite cliffs. To protect the rails and trains from slides, Central Pacific was forced to construct 37 miles of expensive, wooden snowsheds. Where a roadbed could not be built, a tunnel was chipped and blasted out. In the heavy snowbelt between 6,000 and 7,000 feet, nine tunnels were excavated, totaling 5,158 feet in length. At Donner Summit, Tunnel No. 6 was carved through 1,659 feet of solid granite. Despite the constant digging and the use of 300 kegs of black powder daily, the rock was so hard that the Chinese laborers, working around the clock by lanterns and firelight, could gain only about one foot per day. To expedite the work, a vertical shaft seventy-five feet deep was sunk so that crews could work four headers, two from the middle out and two towards the shaft. Stronger than steel

To understand how impenetrable Sierra granite is, consider this description of the resistance encountered boring the railroad tunnels: “The majority [tunnels] were in hard granite, which is often thought of as being similar to marble or limestone. It is actually a very common metamorphic stone even harder than steel or glass, and impervious to virtually all chemicals. It can be polished to a mirror finish, and can bear a compressed load of over 1,000 tons per square foot. A block of granite [the size of a business card] will support a 46-ton locomotive without being crushed.” Black blasting powder had sufficed for the railroad construction until crews reached the core of Sierra granite. After more than a year of twenty-four hour days using black powder on the long Summit Tunnel, Central Pacific Director Charles Crocker ordered his foreman to begin using a new high explosive called nitroglycerin. First discovered in 1846, nitroglycerin was patented in the U.S. by Alfred Nobel on October 24, 1865. Nitro is a clear, odorless, volatile oil thirteen times more powerful than gunpowder and is the active ingredient in dynamite. Unlike black powder, which combusts slower and follows the line of least resistance, nitroglycerin explodes almost instantly in all directions with no regard for resistance met. When CPRR began using the dangerous explosive to bore the Summit Tunnel in January 1867, they were probably the first to do so in the United States. NitroNitroglycerin was much more powerful than black powder, but it also had a nasty reputation for exploding at unexpected times.

In April 1866, the San Francisco Chronicle described a terrible tragedy that resulted when someone tried to open a leaking case of nitroglycerin that had just arrived by steamer from Hamburg, Germany: “The explosion occurred in the office of Wells Fargo & Company by which eight persons lost their lives. It also caused a quarter of a million dollars in damage to the commercial district. A man passing by the Wells Fargo office heard one of the employees address a man riding past on horseback, ‘Doctor we have got a case of glonoin oil and it seems to be smoking, I wish you would step in and advise us what had better be done with it.'” Minutes later the case of nitro exploded. Crocker was understandably reluctant to transport nitroglycerin shipped from Europe, so he arranged for it to be manufactured right on Donner Summit as needed, where it doubled the speed of tunnel excavation. Despite twenty-four hour digging and the harnessed power of dynamite, the Summit Tunnel was not completed until May 3, 1867, nearly two years after the work began.Constructing a railroad 88 miles over the rugged Sierra summit between Newcastle and Truckee, California, had taken 12,000 men 38 months (February 1865 to April 1868). In comparison, the railroad from Truckee across the desert to Promontory, Utah, a distance of 571 miles, took 5,000 men just one year and 27 days. General Sherman was right – conquering the Sierra did take the work of giants, an army of them. Mark McLaughlin’s award-winning books, “Western Train Adventures: The Good, the Bad & the Ugly” and “Sierra Stories: True Tales of Tahoe, Vol. 1 & 2” are available at local bookstores. He can be reached at

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