The railway ascends the mountain beginning at an elevation of approximately above sea level and ending at the summit of Mt. Washington at an elevation of . It is the second steepest rack railway in the world with an average grade of over 25% and a maximum grade of 37.41%. The railway is still in operation, using seven steam locomotives and one biodiesel powered locomotive. The train ascends the mountain at and descends at , although the diesel can go up in as little as 37 minutes. It takes approximately 65 minutes to ascend and 40 minutes to descend. The railway is approximately long.
The railway was built by Sylvester Marsh of Campton, who came up with the idea while climbing the mountain in 1857. His plan was treated as insane. Local tradition says the state legislature voted permission based on a consensus that harm resulting from operating it was no issue — since the design was attempting the impossible — but benefits were guaranteed: The $5,000 of his own money he put up, and whatever else he could raise, would be spent largely locally. The railway is sometimes called "Railway to the Moon" because one state legislator remarked during the proceedings that Marsh should not only be given a charter up Mount Washington but also to the moon. After developing a prototype locomotive and a short demonstration section of track, he found investors and started construction.
Despite its incomplete state, the first paying customers rode in 1868; the construction reached the summit in 1869. The early locomotives all had vertical boilers, like many stationary steam engines of the time; the boilers were mounted on trunnions allowing them to be held vertically no matter what the gradient of the track. Later designs introduced horizontal boilers, slanted so they remain close to horizontal on the steeply graded track.
The first of two major accidents in the railway's history occurred in 1929. The first locomotive, #1 (first named Hero and later Peppersass because of its vertical boiler's resemblance to a pepper sauce bottle) which was used to build the railway was found after being lost for many years as it had been moved about the country and placed on display at many exhibitions. The owners of the railway at the time (the Boston & Maine Railroad) decided to restore Peppersass and make a commemorative trip for the railway's 60th anniversary. During the ascent, however, the locomotive's front axle broke and the locomotive began descending the mountain at high speed. All but one of its crew jumped to safety (though some suffered broken bones), but one man did not escape and died. Although the locomotive broke into pieces, the boiler did not rupture, and the pieces were later reassembled to reconstruct the locomotive for static display. It is now located at the Cog Railway Base Station.
On September 17, 1967, eight passengers were killed and seventy-two injured when Engine #3 derailed at the Skyline switch about a mile below the summit. The engine rolled off the trestle while the uncoupled passenger car slid several hundred feet into a large rock. An investigation revealed that the Skyline switch had not been properly configured for the descending train. The railway nonetheless has a solid safety record having taken almost five million people to the summit during its existence.
Common times for the descent of the mountain using these boards were about 15 minutes. The record was 2:45, an average speed above .
The banning of the Devil's shingles came in 1906 after the death of an employee by accident. Later the design of the rack was changed so the old braking mechanism could not grip any more.
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 sprague 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 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.
The most common trips on the Cog Railway are between the two main stations, one at the summit and the other adjacent to the operators' logistical and repair base.
From 2003 to 2006, "ski trains" ran, stopping at an intermediate station, from which passengers could ski down to the Base Station.
The Cog Railway track crosses a hiking trail a relatively short distance below the summit of Mount Washington, and some hikers wait for the next train in order to moon the passengers. This practice is known as "Mooning the Cog."
Access to the base station by car is by three possible routes, each culminating with the upper portion of the dead-end Cog Base Road. The advertised, roughly eastbound route uses the Base Road's full length from Bretton Woods. An especially scenic route, initially southbound from U.S. Highway 2, follows Jefferson Notch Road, a narrow dirt road with hairpin turns; it rises to the pass, at above sea level, between Mount Jefferson in the Presidential Range and Mount Dartmouth, before descending to its junction with the Base Road. However, in winter, and usually before and after, the Jefferson Notch Road is closed to wheeled vehicles and used primarily by snowmobiles. The initially roughly northbound route from U.S. Highway 302 in Crawford Notch via Mt. Clinton Road is also closed in the winter to vehicular traffic. Due to the operations of trains all winter beginning in 2004-2005 the Cog Base Road is now plowed and sanded all winter to allow tourists, skiers and employees to access the Base Station.
Each ride burns of coal and consumes of water.
One steam locomotive was converted to biodiesel in 2008.
|1||Peppersass||Campbell, Whittier and Company||Steam locomotive||1866||World's first cog locomotive, originally named Hero. Last operated in 1929, and is now on display at Marshfield Station.|
|1||Mt. Washington||Manchester Locomotive Works||Steam locomotive||1883||Was the first #7 Falcon; renumbered to 1 following rebuilding after the 1895 fire. Renamed Mt. Washington after 1931. Currently stored out of service at the shops.|
|2||Ammonoosuc||Manchester Locomotive Works||Steam locomotive||1875||Was second #4 Atlas; renumbered to 2 following rebuilding after the 1895 fire. Named Ammonoosuc after 1931.|
|3||Agiocochook||Manchester Locomotive Works||Steam locomotive||1883||Originally #2 of the Green Mountain Cog Railway. Was the third #5, not named; became the third #3 in 1934. Renamed Agiocochook in 1995/96.|
|4||Chocorua||Manchester Locomotive Works||Steam locomotive||1883||Originally #1 of the Green Mountain Cog Railway. Became the third #4. Was named the Summit.|
|6||Kancamagus||Manchester Locomotive Works||Steam locomotive||1874||Originally built as first #6 Tip-Top with vertical boiler. Rebuilt into second #6 in 1878 with horizontal boiler. Was named Great Gulf.|
|8||Moosilauke||Mt. Washington Cog Railway Shop||Steam locomotive||1983||Uses a larger, welded boiler built by Munroe Boiler. Was named Tip Top.|
|9||Waumbek||Manchester Locomotive Works||Steam locomotive||1908||First horizontal boilered engine to have the cab on the same plane as the boiler. For a short time, this locomotive burned biodiesel, but was reconverted to coal.|
|10||Kroflite||Mt. Washington Cog Railway Shop||Steam locomotive||1972||Uses a larger, welded boiler built by Munroe Boiler. Has the cab tilted on the same plane as the boiler. Converted to burn oil for a short time and converted back to coal. Was named the Col. Teague.|
|M-1||Wajo Nanatasis||Mt. Washington Cog Railway Shop||Diesel locomotive||2008||Unique diesel-hydraulic locomotive.|