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Rack railway
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A cog railway, pens and rails railway, rack-and-pinion railway or rack railway is a railway with a toothed rack rail, usually between the running rails.
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Encyclopedia
A cog railway, pens and rails railway, rack-and-pinion railway or rack railway is a 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 gradients.
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, UK, where the first commercial steam locomotive, The 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 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.
Rack systems
A number of different rack systems have been developed. Today, the majority of rack railways use the Abt system.
Trevithick
Thinking that the friction of metal wheels on metal rails would be too low, Richard Trevithick built his first experimental locomotives with teeth on the wheels on one side that engaged in teeth on the rails on the same side. That a rack mechanism wasn't really necessary on tracks with only gentle gradients wasn't considered.
In 1812, the Middleton Railway under the management of John Blenkinsop adopted the Trevithick design when it introduced steam locomotive and had to keep the weight (and friction) low so as to avoid breaking the fragile cast iron rails.
All other rack systems place the rack rail halfway between the running rails.
Stephenson
George Stephenson grouped the steep gradients on either side of Rainhill and from Liverpool down to the wharfs, just in case cable haulage was necessary. In the event, only the wharf line needed cable haulage for a few decades.
Marsh
The first successful rack railway in the US was the Mount Washington Cog Railway, developed by Sylvester Marsh. Marsh developed and tested his rack system and on 10 September 1861 he was issued a US patent for his invention. The Mount Washington railway opened in 1869, using Marsh's central rack which employed parallel wrought iron angle bars, connected by regularly spaced pins. The pinion wheels on the locomotives had deep teeth that ensure that at least two teeth are engaged with the rack at all times - this measure helps reduce the possibility of the pinions riding up and out of the rack.
Riggenbach
The Riggenbach rack system was invented by Niklaus Riggenbach working at about the same time as, but independently from Marsh. Riggenbach was granted a French patent in 1863 based on a working model which he used to interest potential Swiss backers. During this time, the Swiss Consul to the United States visited Marsh's Mount Washington Cog Railway and reported back with enthusiasm to the Swiss government. Eager to boost tourism in Switzerland, the government commissioned Riggenbach to build a rack railway up Rigi Mountain. Following the construction of a prototype locomotive and test track in a quarry near Berne, the Vitznau-Rigi-Bahn opened on 22 May 1871.
The Riggenbach system is similar in design to the Marsh system. It uses a ladder rack, formed of steel plates or channels connected by round or square rods at regular intervals. The Riggenbach system suffers from the problem that its fixed ladder rack is more complex and expensive to build than the other systems.
Common structural shapes
Following the success of the Vitznau-Rigi-Bahn, Riggenbach established the Maschinenfabrik der Internationalen Gersellschaft fur Bergbahnen (IGB) - a company that produced rack locomotives to his design.
Strub
The Strub rack system was invented by Emil Strub in 1896. It uses a rolled flat-bottom rail with rack teeth machined into the head approximately 100 mm apart. Safety jaws fitted to the locomotive engage with the underside of the head to prevent derailments.
The best-known use of the Strub system is on the Jungfraubahn in Switzerland. It is the simplest rack system to maintain and has become increasingly popular .
Abt
The Abt system was devised by Roman Abt, a Swiss locomotive engineer. Abt worked for Riggenbach at his works in Olten and later at his IGB rack locomotive company. In 1885 he founded his own civil engineering company.
During the early 1880s, Abt worked to devise an improved rack system that overcame the limitations of the Riggenbach system. In particular, the Riggenbach rack was expensive to manufacture and maintain and the switches were complex. In 1882 Abt designed a new rack using solid bars with vertical teeth machined into them. Two or three of these bars are mounted centrally between the rails, with the teeth offset. The use of multiple bars with offset teeth ensures that the pinions on the locomotive driving wheels are constantly engaged with the rack. The Abt system is cheaper to build than the Riggenbach because it requires a lower weight of rack over a given length. However the Riggenbach system exhibits greater wear resistance than the Abt.
The first use of the Abt system was on the Harzbahn in Germany which opened in 1885.
The pinion wheels can be mounted on the same axle as the rail wheels (as in the picture at right), or driven separately. The steam locomotives on the Mount Lyell Mining and Railway Company had separate pistons driving the pinion wheel.
Locher
The Locher rack system, invented by Eduard Locher, has 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.
Locher set out to design a rack system that could be used on gradients as steep as 1 in 2 (50%). The Abt system - the most common rack system in Switzerland at the time - was limited to a maximum gradient of 1 in 4 (25%). Locher showed that on steeper grade, the Abt system was prone to the driving pinion over-riding the rack causing potentially catastrophic derailments, as predicted by Dr. Abt.
To overcome this problem and allow a rack line up the steep sides of Mt. Pilatus, Locher developed a rack system where the rack is a flat bar with symmetrical, horizontal teeth. Horizontal pinion engage the centrally-mounted bar, both driving the locomotive and keeping it centered on the track.
Following tests, the Locher system was deployed on the Pilatus Railway which opened in 1889. No other public railway uses the Locher system, although some European coal mines use a similar system on steeply graded underground lines.
Lamella
The Lamella system (also known as the Von Roll system) was developed by the Von Roll company after the rolled steel rails used in the Strub system became unavailable. It is formed from a single blade cut in a similar fashion to the Abt system but typically wider than a single Abt bar. The Lamella rack can be used by locomotives designed for use on the Riggenbach or the Strub systems and some railways use rack from multiple systems. The St. Gallen Gais Appenzell Railway in Switzerland has sections of Riggenbach, Strub and Lamella rack.
Most of the rack railways built from the late 20th century onwards have used the Lamella system.
Rack-and-adhesion systems / Pure rack systems
Rack-and-adhesion systems use the cog drive only on the steepest sections and elsewhere operate as 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. In this case the racks continue also in the horizontal parts, if any.
Fell
The Fell mountain railway system is not strictly speaking a rack railway since there are no cogs with teeth. Rather, this system uses a smooth raised centre rail between the two running rails on steep lines which is gripped on both sides to improve friction. Trains are propelled by wheels or braked by shoes pressed horizontally onto the centre rail, as well as by means of the normal running wheels.
Switches
Cog locomotives
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.
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.
The maximum speed of trains operating on a cog railway is generally very low, about 25 km/h .
List of cog and rack railways
See also list of mountain railways
Argentina
Australia
Austria
Bolivia
Brazil
Chile
Czech republic
France
Germany
- Drachenfels Railway
- Harzbahn (Rübelandbahn)
- Höllentalbahn (adhesion only since 1933)
- Oberweißbacher Bergbahn
- Schwarzatalbahn
- Stuttgart Rack Railway, Stuttgart
- Wendelsteinbahn
- Zugspitze Railway
Greece
Hungary
Indonesia
- Aceh - no longer in operation but will be reconstructed.
- Bedono - still in operation as a tourist line using steam locomotives.
India
Uses steam engines [WORLD HERITAGE CERTIFIED]
Italy
- Vesuvius Funicular (1880-1944; originally built as funicular and then changed to rack railway. It was the only railway climbing an active volcano. It was destroyed various times by Vesuvius eruptions. With last destruction in 1944, it was never built again. It is worldwide famous for the sing Funiculì Funiculà entitled to it).
- Opicina Tramway (1902–1928; rack replaced with a funicular section)
- Rittnerbahn (rack section closed)
- Superga Rack Railway
- Ferrovia Principe-Granarolo
Japan
- Ikawa Line, Oigawa Railway
- Usui Pass was the first rack and pinion line in Japan, on the Shin-Etsu Line of the then Japanese National Railway. It was replaced in 1963 by a new parallel adhesion line, themselve replaced by the Nagano Shinkansen line for the Nagano olympic games.
Lebanon
- A rack railway used to exist on the climb from Beirut to Syria, gauge .
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.
Slovakia
Spain
Switzerland
not a rack railway but similar technology
- Wädenswil-Einsiedeln-Bahn
See also
United Kingdom
Fell system railway (not rack):
United States
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.
See also
External links
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