Rack railway

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Image:Lausanne Metro Track Closeup.jpg
Rack railway track using Von Roll system rack.
Image:Cog railway Schneeberg.jpeg
Schneeberg cog railway steam locomotive, with tilted boiler, on level track.

A cog railway, rack-and-pinion railway or rack railway is a railway with a special toothed rack rail or rack mounted on the railroad ties (sleepers), 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 steeply inclined slopes.

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 in the world was the Middleton Railway in Leeds where the first commercial steam locomotive, The Salamanca ran in 1812. This used a rack and pinion system designed by John Blenkinsop.

The first mountain cog railway was the Mount Washington Cog Railway in the US state of New Hampshire, which carried its first fare-paying passengers in 1868 and reached the summit of Mount Washington in 1869. The first rack railway in Europe was the Vitznau-Rigi-Bahn on Mount Rigi in Switzerland, which opened in 1871. Both lines are still running today.


[edit] Rack systems

Image:Riggenbach, Strub, Abt, Locher.jpg
Different rack systems: from the left, Riggenbach, Strub, Abt and Locher.

A number of different rack systems have been developed.

[edit] Riggenbach rack system

The Riggenbach rack system

The Riggenbach rack system, invented by Niklaus Riggenbach, is the oldest form of rack railway and uses a ladder rack, formed of steel plates or channels connected by round or square rods at regular intervals. The Riggenbach system was the first system devised, and suffers from the problem that its fixed rack is much more complex and expensive to build than the other systems. This system is sometimes known as the Marsh rack system, because of simultaneous invention by an American inventor, Sylvester Marsh, builder of the Mount Washington Cog Railway.

[edit] Strub rack system

Image:365px-Zahnradbahn strub.jpg
The Strub rack system

The Strub rack system, invented by Emil Strub, is similar to the Abt rack system but uses just one wide rack plate welded on top of a flat bottom T railway rail. It is the simplest rack system to maintain and has become increasingly popular.

[edit] Abt rack system

The Abt rack system was devised by Roman Abt, a Swiss locomotive engineer working for a Riggenbach-equipped line, as an improved rack system. The Abt rack features steel plates mounted vertically and in parallel to the rails, with rack teeth machined to a precise profile in them. These engage with the locomotive's pinion teeth much more smoothly than the Riggenbach system. Two or three parallel sets of Abt rack plates are used, with a corresponding number of driving pinions on the locomotive, to ensure that at least one pinion tooth is always engaged securely.

Today, the majority of rack railways use the Abt system.

[edit] Locher rack system

Locher rack system
Image:Pilatus Rack.jpg
Locher Rack system (seen from above)

The Locher rack system, invented by Eduard Locher, involves gear teeth cut in the sides rather than the top of the rail, engaged by two cog wheels on the locomotive. This system allows use on steeper grades than the other systems, whose teeth could jump out of the rack. It is used on the Pilatus Railway.

[edit] Von Roll rack system

The Von Roll rack system, by the von Roll company, is similar to the Abt system, except that the teeth in the single blade are cut to suit the gear geometry of either the Riggenbach system cog or the Strub system cog (or gear) wheels. Because of its simplicity, the Von Roll rack replaces the Riggenbach or Strub rack in new, or replacement, installations without the need to replace the cogs (or pinions) on the electric locomotives or EMU passenger cars.

[edit] Rack and adhesion systems / Pure rack systems

Some rail systems, known as 'rack-and-adhesion', use the cog drive only on the steepest sections and elsewhere operate like a regular railway. Others, the steeper ones, are rack-only. On the latter type, the locomotives' wheels are generally free-wheeling and despite appearances do not contribute to driving the train.

[edit] Cog locomotives

Image:Pikes Peak Locomotive.jpg
Pike's Peak cog steam locomotive on steeply graded track, showing the tilted boiler level.

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.

Image:Ferrovia Renon.jpg
Early electric cog locomotive and carriage

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 of the railway. 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.

On a rack-only railroad locomotives always push their passenger cars for safety reasons since 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.

[edit] Speed

The maximum speed of trains operating on a cog railway is generally very low, about 25 km/h [citation needed].

[edit] List of cog and rack railways

[edit] Argentina

[edit] Australia

The Schneebergbahn.

[edit] Austria

[edit] Brazil

  • Corcovado Rack Railway
  • The Serra do Mar line, originally part of Estrada de Ferro Santos a Jundiaí, part of Rede Ferroviária Federal Sociedade Anônima (RFFSA) 1957-1997, now owned by MRS Logística

[edit] Chile

[edit] Czech republic

[edit] France

[edit] Germany

[edit] Greece

[edit] Hungary

[edit] India

[edit] Italy

[edit] Japan

[edit] Lebanon

  • A rack railway used to exist on the climb from Beirut to Syria, gauge 1050 mm.

[edit] New Zealand

[edit] Panama

  • Large ships are guided through the Panama Canal Locks by electric locomotives known as mulas (mules), running on rack rails on the lock walls rather than proceeding under their own power. The new locks approved in 2006 will use tugs.

[edit] Slovakia

[edit] Spain

[edit] Switzerland

[edit] See also

[edit] United Kingdom

[edit] United States

Image:Mount Washington Cog Railway Start.jpg
The Mount Washington Cog Railway in 2006

[edit] Rack railways in fiction

The Culdee Fell Railway is a fictional cog railway on the Island of Sodor in The Railway Series by Rev.W.Awdry. Its operation, locomotives and history are at least in part based on the Snowdon Mountain Railway. It is featured in the book Mountain Engines.

[edit] See also

[edit] External links

da:Tandhjulsbane de:Zahnradbahn es:Ferrocarril de cremallera fr:Chemin de fer à crémaillère id:Jalur rel gigi it:Ferrovia a cremagliera ja:ラック式鉄道 nl:Tandradspoorweg Cremalheira em ferrovias sv:Kuggstångsbana zh:齒軌鐵路

Rack railway

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