Born near West Gardiner, Maine, on April 25, 1853, Stevens originally studied to be a teacher. At the age of 21, with no technical training, he moved to Minneapolis to take a job in the city engineer’s office. Later, he entered the growing industry of railroad location and construction in several western states. He undertook his first major engineering assignment in 1883, as an assistant to the chief engineer responsible for scouting locations for the Canadian Pacific Railroad’s crossing of the Rocky Mountains. By the age of 33, Stevens was principal assistant engineer for the Duluth, South Shore, and Atlantic Railway in Minnesota, and in charge of building the line from Duluth to Sault Ste. Marie, across Michigan’s Upper Peninsula.
In 1889, Stevens was hired by James J. Hill, who had ambitious plans to link the Midwest with the Pacific Northwest via a route south of the Canadian border. Hill hired Stevens as a locating engineer for the Great Northern Railway. During this time, Stevens charted the Marias Pass over the Continental Divide. He was the first to explore the pass as a location engineer, to judge its practicability for a railroad, and to make the findings public. In honor of this achievement, Stevens Pass, in the Cascade Range, was named for him. In 1895, Hill promoted Stevens to chief engineer and later to general manager. During his tenure at Great Northern Railway, Stevens built more than 1,000 miles of railroad, including the original Cascade Tunnel. He also oversaw the construction of Hill’s Great Northern Railway. In 1903, Stevens went to work for the Chicago, Rock Island and Pacific Railroad, where he was promoted to vice-president.
In 1905, Stevens was selected to be the chief engineer for the Panama Canal project. Arriving in Panama, he found what he called “about as discouraging a proposition as was ever presented to a construction engineer.” The workers were suffering from malaria, yellow fever, poor housing, and malnutrition. The project had little excavating equipment on hand and the transportation system was in disrepair.
Stevens understood that his first task was to restore morale. “The digging,” he said, “is the least thing of all.” He immediately began to build warehouses, machine shops, and piers. Communities for the personnel were planned and built to include housing, schools, hospitals, churches, and hotels. He authorized extensive sanitation and mosquito-control programs that eliminated yellow fever and other diseases from the Isthmus. Stevens saw the early stage of the canal project itself as primarily a problem in railroad engineering. To remedy this he rebuilt the Panama Railway and devised a rail-based system for disposing of the soil from the excavations. Despite many challenges, Stevens was able to build the infrastructure needed for the completion of the canal.
He was also instrumental in persuading President Theodore Roosevelt to build the canal with locks, this in the face of opposition from skeptics who preferred a sea-level canal which would have required much more extensive excavation. During Stevens’ tenure, he encountered continuing political difficulties as well. In 1907, he resigned from the canal project and returned to the U.S. to resume his railroad work.
In 1917, he was appointed by President Woodrow Wilson to the American Advisory Commission of Railway Experts to Russia, and tasked with improving the Chinese Eastern and Trans-Siberian railroads to better supply troops to the front during World War I. After the fall of the Russian government, which took the newly formed Soviet Union out of the fighting, Stevens formed the Inter-Allied Technical Board under the auspices of the State Department. Headquartered in Harbin, Manchuria, the board worked to protect Allied interests along the railway. In 1923, Stevens returned to the U.S. to work as a consulting engineer, ending his career in Baltimore in the early 1930s. He retired in Southern Pines, North Carolina, where he died at the age of 90 on June 2, 1943. Stevens is buried in the Mount Hope Cemetery in Mattapan, Massachusetts.