page_title: Rack railway
section_title: Switches
hierarchical_section_title: Rack railway / Switches
caption_attribution_description: English: A railroad switch (railway turnout) on the Schynige Platte-Bahn (SPB, Schynige Platte Railway) rack railway in Switzerland. Note the mechanism to allow the locomotive's driving pinion to engage with the rack as it passes over the switch. The image was captured immediately southwest of the station at Schynige Platte.
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: Rack railway switches are as varied as rack railway technologies, for optional rack lines such as the Zentralbahn in Switzerland and the West Coast Wilderness Railway in Tasmania it is convenient to only use switches on sections flat enough for adhesion (for example, on a pass summit).  Other systems which rely on the rack for driving (with the conventional rail wheels undriven) such as the Dolderbahn in Zurich, Štrbské Pleso in Slovakia and the Schynige Platte rack railway instead must switch the rack rail.  The Dolderbahn switch works by bending all three rails, an operation that is performed every trip as the two trains pass in the middle.
  The geometry of the rack system has a large impact on the construction of turnouts.  If the rack is elevated above the running rails, there is no need to interrupt the running rails to allow passage of the driving pinions of the engines.  Strub explicitly documented this in his U.S. patent.  Strub used a complex set of bell-cranks and push-rods linking the throw-rod for the points to the two throw-rods for the moving rack sections.  One break in the rack was required to select between the two routes, and a second break was required where the rack rails cross the running rails.  Turnouts for the Morgan Rack system were similar, with the rack elevated above the running rails.  Most of the Morgan turnout patents included movable rack sections to avoid breaks in the rack, but because all Morgan locomotives had two linked drive pinions, there was no need for a continuous rack.  So long as the breaks in the rack were shorter than the distance between the drive pinions on the locomotive, the rack rail could be interrupted wherever there was need to cross over a running rail.
  Turnouts are far more complex when the rack is at or below the level of the running rails.  Marsh's first rack patent shows such an arrangement, and the original Mount Washington Cog Railway he built had no turnouts.  It was not until 1941 that a turnout was constructed on this line.  There were more turnouts built for the line but all were hand operated. In 2003, a new automatic hydraulic turnout was developed and built at the base as a prototype. With the success of the new turnout, more new automatic hydraulic turnouts were built to replace the hand-operated ones. The new turnouts installed on the Mount Washington line in 2007 are essentially transfer tables. The Locher rack also requires transfer tables.
caption: Railroad switch on a rack railway.  The turnout uses Lamella rack rails, but the overall design was pioneered by Strub.  The track outside the turnout uses Riggenbach rack rails. (Schynige Platte Railway, Switzerland)
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