page_title: Rack railway
section_title: Cog locomotives
hierarchical_section_title: Rack railway / Cog locomotives
context_page_description: 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 grades above 10%, which is the maximum for friction-based rail. 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.
  The first mountain cog railway was the Mount Washington Cog Railway in the U.S. state of New Hampshire, which carried its first fare-paying passengers in 1868. The track was completed to reach the summit of Mount Washington in 1869. The first mountain rack railway in continental Europe was the Vitznau-Rigi-Bahn on Mount Rigi in Switzerland, which opened in 1871. Both lines are still running.
context_section_description: Originally almost all cog railways were powered by steam locomotives.  The steam locomotive needs to be extensively modified to work effectively in this environment.  Unlike a Diesel locomotive or electric locomotive, the steam locomotive only works when its powerplant (the boiler, in this case) is fairly level.  The locomotive boiler requires water to cover the boiler tubes and firebox sheets at all times, particularly the crown sheet, the metal top of the firebox.  If this is not covered with water, the heat of the fire will soften it enough to give way under the boiler pressure, leading to a catastrophic failure.
  On rack systems with extreme gradients, the boiler, cab and general superstructure of the locomotive are tilted forward relative to the wheels so that they are more or less horizontal when on the steeply graded track.  These locomotives often cannot function on level track, and so the entire line, including maintenance shops, must be laid on a gradient. This is one of the reasons why rack railways were among the first to be electrified and most of today's rack railways are electrically powered. In some cases, a vertical boiler can be used that is less sensitive for the track gradient.
  On a rack-only railroad, locomotives are always downward of their passenger cars for safety reasons: the locomotive is fitted with powerful brakes, often including hooks or clamps that grip the rack rail solidly.  Some locomotives are fitted with automatic brakes that apply if the speed gets too high, preventing runaways.  Often there is no coupler between locomotive and train since gravity will always push the passenger car down against the locomotive.  Electrically powered vehicles often have electromagnetic track brakes as well.
  The maximum speed of trains operating on a cog railway is very low, generally from 9 to 25 kilometres per hour (5.6 to 15.5 mph) depending on gradient and propulsion method.  Because the Skitube has gentler gradients than typical, its speeds are higher than typical.
caption: Rittnerbahn early electric cog locomotive and carriage
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