Mount Washington Cog Railway - Mechanical Design

Mechanical Design

Each train consists of a locomotive pushing a single passenger car up the mountain, and descending the mountain by going backwards. Both locomotive and car were originally equipped with a ratchet and pawl mechanism engaged during the climb that prevents any roll-back; during descent, both locomotive and car are braked. Recent improvements in design have replaced the ratchet (gear and pawl mechanism) with sprag clutches and disc brake assemblies. Most of the locomotives were made by the Manchester Locomotive Works.

The rack rail design used is one of Marsh's own invention, using a ladder-like rack with open bar rungs engaged by the teeth of the cog wheel. This system allows snow and debris to fall through the rack rather than lodge in it. A similar design, called the Riggenbach rack system, was invented by engineer Niklaus Riggenbach in Switzerland at about the same time. The Swiss Consul to the United States visited Marsh while constructing the railway up Mount Washington, and his enthusiastic reports persuaded the Swiss government to commission Riggenbach to build on Rigi Mountain the Vitznau-Rigi-Bahn, opened on May 21, 1871.

Initially, there was no way to pass on the Mount Washington Cog Railway. In 1941, a nine-motion switch was invented, and two spur sidings were added, each long enough to divert two up trains so others could pass down, enabling more round trips per day.

In 2004, work was completed replacing the lower Waumbek Switch and Siding with an 1,800-foot (550 m) passing loop equipped with electric and hydraulicly powered automated switches. These switches are powered by batteries and recharged by solar panels. One switch is located at each end of the loop, allowing ascending and descending trains to pass one another.