The Mount Washington Cog Railway opens, making it the world's first mountain-climbing rack railway.

The Mount Washington Cog Railway, also known as the Cog, is the world's first mountain-climbing cog railway. The railway climbs Mount Washington in New Hampshire, United States. It uses a Marsh rack system and both steam and biodiesel-powered locomotives to carry tourists to the top of the mountain. Its track is built to a 4 ft 8 in gauge, which is technically a narrow gauge, as it is 1⁄2 inch (13 mm) less than a 4 ft 8+1⁄2 in standard gauge.

A rack railway is a steep grade railway with a toothed rack rail, usually between the running rails. The trains are fitted with one or more cog wheels or pinions that mesh with this rack rail. This allows the trains to operate on steep gradients of 100% or more, well above the 10% maximum for friction-based rail. The rack and pinion mechanism also provides more controlled braking and reduces the effects of snow or ice on the rails. Most rack railways are mountain railways, although a few are transit railways or tramways built to overcome a steep gradient in an urban environment. The first cog railway was the Middleton Railway between Middleton and Leeds in West Yorkshire, England, United Kingdom, where the first commercially successful steam locomotive, Salamanca, ran in 1812. This used a rack and pinion system designed and patented in 1811 by John Blenkinsop.