The railroad's best-known engineer was John Frank Stevens, who served from 1889 to 1903. Stevens was acclaimed for his 1889 exploration of Marias Pass in Montana and determined its practicability for a railroad. Stevens was an efficient administrator with remarkable technical skills and imagination. He discovered Stevens Pass through the Cascade Mountains, set railroad construction standards in the Mesabi Range, and supervised the construction of the Oregon Trunk Line. He then became the chief engineer of the Panama Canal.