The Milwaukee Road faced the daunting task of drilling a tunnel 23 feet high, 16 feet wide and 1.7 miles long into Idaho.

It was a damp, dark, dirty dig. After the approaches were prepared in 1906, and a faltering start in 1907, work began in earnest in 1908. East and west crews toiled around the clock in wet, miserable conditions, and at their best could tunnel 20 feel a day. A company official remembered that:

“Men were hard to keep as the work was disagreeable and hard. Several large veins of water were encountered and at times the working conditions were almost unbearable.”

It took 750 men--400 tunneling inside, 200 outside removing the dirt and rock, and 150 running the dig’s power plant yards--two and a half years to complete.

The steam-driven electric power plant set up four miles away in Taft, Montana powered both ends of the dig. Compressed air provided safe, smokeless power to the giant steam shovels that loaded the blasted, broken rock into electric rail cars for removal.