In the summer of 1866, to move farther faster, the railroad kept several shifts of men going day and night. Shoulder to shoulder, hour after hour, the Chinese railroad workers chipped away at the rock, breathing granite dust, sweating and panting by the dim flickering glow of candlelight, until even the strongest of them fainted from exhaustion.

Finally, to speed up the process, the Central Pacific brought in nitroglycerin. Only the Chinese—a people experienced with fireworks—were willing to handle this unpredictable explosive, pouring it into the tunnel through holes drilled in the granite. Countless workers perished in accidental blasts, but the Central Pacific did not keep track of the numbers. (Chang 59)