Which New Hampshire cog railway first reached Mount Washington's summit in 1869?

The Mount Washington Cog Railway was the New Hampshire railway that first reached Mount Washington’s summit in 1869. Construction reached the summit in July 1869, creating the world’s first mountain-climbing cog railway and demonstrating that a rack-and-pinion system could carry trains up exceptionally steep grades.

The project was developed by Sylvester Marsh, who formed the Mount Washington Railway Company in 1866. Its track uses the Marsh rack system: a toothed rail engages with a cogwheel on the locomotive, providing traction where ordinary adhesion between steel wheels and rails would be insufficient. The railway follows a route near an earlier mountain trail.

The line began carrying paying passengers before it was complete, with early rides starting on 14 August 1868. Its first steam locomotives had vertical boilers mounted so they could pivot on the steep incline, keeping the boilers oriented more safely as the train climbed.

The Mount Washington line is often confused with the Pilatus Railway in Switzerland, which is steeper but opened later, in 1889. The Snowdon Mountain Railway and Manitou and Pike’s Peak Railway also came afterward.