Alaska's 

White Pass and Yukon Route

Skagway, Alaska

The narrow gauge White Pass and Yukon Route climbs nearly 3000 feet from sea level to White Pass Summit in 20 miles with grades up to 3.9%. It was built from 1898 to 1900 to serve the Klondike Gold Rush and was the northernmost railroad in the Western Hemishere. Thirty thousand men worked on the route and used 450 tons of explosives (black powder) to construct the 110 miles of track, 2 tunnels, and numerous trestles and bridges.

The Steel Cantilever Bridge, the tallest in the world when built, is no longer used but is often photographed. The WP&YR was designated one of only 36 world civil engineering marvels in 1994 due to the many hazardous obstacles that construction had to overcome. During World War II, the railroad was the chief supplier for construction of the Alaska Highway. In 1954 they changed to diesel electric motive power. 1955, the route pioneered the inter-modal "Container Route" and in 1988 began service as a tourist attraction.

This photo from the train's brochure shows the perspective of the train on the ledge as it approaches a trestle and then Tunnel Mountain.