Though compressed-air drills existed at the time, all blasting holes here were drilled by hand using hammers and bits, the tools held by the drillers in this photograph. The bits were simply steel rods with ends forged into chisel-shaped points. One man would hold and rotate the bit, while two others alternately struck it with sledgehammers. Once drilled, the holes were filled with black powder (later with nitroglycerin). After detonation, the broken pieces of rock were loaded by hand into carts and removed from the tunnel. In Summit Tunnel, this went on 24 hours a day, seven days a week, for 15 months. From 30 to 40 Chinese worked at each of the four faces, with half drilling and the rest clearing out rubble from previous blasts.
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