Atmospheric railway
Encyclopedia
Pneumatic tube
Pneumatic tubes are systems in which cylindrical containers are propelled through a network of tubes by compressed air or by partial vacuum...
is laid between the rails, with a piston running in it suspended from the train through a sealable slot in the top of the tube. Alternatively, the whole tunnel may be the pneumatic tube with the car being the piston with a seal to the walls. By means of stationary pumping engines along the route, air is exhausted from the tube leaving a partial vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
in advance of the piston or car, and air is admitted to the tube behind the piston or car so that atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
propels the train. In some plans, air pressure is applied behind the piston/car.
Historical applications
In 1799 George MedhurstGeorge Medhurst
George Medhurst was a mechanical engineer and inventor, who pioneered the use of compressed air as a means of propulsion. His ideas led directly to the development of the first atmospheric railway....
of London discussed the idea of moving goods pneumatically through cast iron pipes, and in 1812 he proposed, but never implemented, blowing passenger carriages through a tunnel.
In 1835 Henry Pinkus launched a prospectus for the National Pneumatic Railway Association. It was in 1838, when the gas engineer Samuel Clegg
Samuel Clegg
Samuel Clegg was a British civil engineer.Clegg was born at Manchester on 2 March 1781, received a scientific education under the care of Dr. Dalton. He was then apprenticed to Boulton and Watt, and at the Soho Manufactory witnessed many of William Murdoch's earlier experiments in the use of coal...
and the marine engineers Jacob and Joseph Samuda
Samuda Brothers
Samuda Brothers was an engineering and ship building firm at Cubitt Town on the Isle of Dogs in London, founded by Jacob and Joseph d'Aguilar Samuda. The site is now occupied by Samuda Estate....
jointly took out a patent “for a new improvement in valves” that atmospheric propulsion became possible. The partnership set up a working model at the Samuda Brothers’ workshop in Southwark
Southwark
Southwark is a district of south London, England, and the administrative headquarters of the London Borough of Southwark. Situated east of Charing Cross, it forms one of the oldest parts of London and fronts the River Thames to the north...
in 1839, and a 0.5 mile (0.80467 km) demonstration track of the Birmingham, Bristol & Thames Junction Railway at Wormwood Scrubs
Wormwood Scrubs
Wormwood Scrubs, known locally as The Scrubs, is an open space located in the north-eastern corner of the London Borough of Hammersmith and Fulham in west London. It is the largest open space in the Borough, at 80 ha , and one of the largest areas of common land in London...
between 1840 and 1843. In 1841 Joseph d'Aguilar Samuda
Joseph d'Aguilar Samuda
Joseph d'Aguilar Samuda was an English civil engineer and politician. He was born in London the younger son of Abraham Samuda, and brother of Jacob Samuda...
published A Treatise on the Adaptation of Atmospheric Pressure to the Purposes of Locomotion on Railways
The Clegg-Samuda system attracted the attention and support of some of the foremost railway engineers of the day, notably William Cubitt
William Cubitt
Sir William Cubitt was an eminent English civil engineer and millwright. Born in Norfolk, England, he was employed in many of the great engineering undertakings of his time. He invented a type of windmill sail and the prison treadwheel, and was employed as chief engineer, at Ransomes of Ipswich,...
, Charles Vignoles and Isambard Kingdom Brunel
Isambard Kingdom Brunel
Isambard Kingdom Brunel, FRS , was a British civil engineer who built bridges and dockyards including the construction of the first major British railway, the Great Western Railway; a series of steamships, including the first propeller-driven transatlantic steamship; and numerous important bridges...
, each of whom was engaged on the construction of new railway lines. It was also severely criticised by other engineers and railway commentators, notably Robert Stephenson
Robert Stephenson
Robert Stephenson FRS was an English civil engineer. He was the only son of George Stephenson, the famed locomotive builder and railway engineer; many of the achievements popularly credited to his father were actually the joint efforts of father and son.-Early life :He was born on the 16th of...
and John Herapath
John Herapath
John Herapath was an English physicist who gave a partial account of the kinetic theory of gases in 1820 though it was neglected by the scientific community at the time....
.
Dalkey Atmospheric Railway
The first practical use of the system was on the Dublin and Kingstown RailwayDublin and Kingstown Railway
The Dublin and Kingstown Railway , which opened in 1834, was Ireland’s first railway. It linked Westland Row in Dublin with Kingstown Harbour’s West Pier in County Dublin.-History:...
's Dalkey Atmospheric Railway
Dalkey Atmospheric Railway
The Dalkey Atmospheric Railway was an extension of the Dublin and Kingstown Railway to Atmospheric Road in Dalkey, Co. Dublin, Ireland. It used part of the Dalkey Quarry industrial tramway, which was earlier used for the construction of Kingstown Harbour...
between Kingstown (Dún Laoghaire
Dún Laoghaire
Dún Laoghaire or Dún Laoire , sometimes anglicised as "Dunleary" , is a suburban seaside town in County Dublin, Ireland, about twelve kilometres south of Dublin city centre. It is the county town of Dun Laoghaire-Rathdown County and a major port of entry from Great Britain...
) and Dalkey
Dalkey
Dalkey is suburb of Dublin and seaside resort in Dun Laoghaire-Rathdown County, Ireland. It was founded as a Viking settlement and became an important port during the Middle Ages. According to John Clyn, it was one of the ports through which the plague entered Ireland in the mid-14th century...
, Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
, This 1.75 miles (2.8 km) line was built by Vignoles and operated between 1844 and 1854.
London and Croydon Railway
Cubitt recommended the system for the 7.5 miles (12.1 km) London and Croydon RailwayLondon and Croydon Railway
The London and Croydon Railway was an early railway which operated between London and Croydon in England. It was opened in 1839 and in July 1846 it merged with other railways to form a part of the London Brighton and South Coast Railway ....
between London Bridge station
London Bridge station
London Bridge railway station is a central London railway terminus and London Underground complex in the London Borough of Southwark, occupying a large area on two levels immediately south-east of London Bridge and 1.6 miles east of Charing Cross. It is one of the oldest railway stations in the...
and Croydon
Croydon
Croydon is a town in South London, England, located within the London Borough of Croydon to which it gives its name. It is situated south of Charing Cross...
. Clegg and Samuda were invited by the directors to supply equipment to operate their trains between London Bridge
London Bridge station
London Bridge railway station is a central London railway terminus and London Underground complex in the London Borough of Southwark, occupying a large area on two levels immediately south-east of London Bridge and 1.6 miles east of Charing Cross. It is one of the oldest railway stations in the...
and Epsom
Epsom railway station
Epsom railway station is the main railway station for Epsom in the county of Surrey. It is located off Waterloo Road, near to the High Street....
. The first stage of this project (between Croydon
West Croydon station
West Croydon station is a transport interchange for National Rail and Tramlink services, as well as London Buses. It is in the London Borough of Croydon and Travelcard Zone 5...
and Forest Hill
Forest Hill railway station
Forest Hill railway station is situated in Forest Hill, part of the London Borough of Lewisham. The station is located on the South Circular Road ....
) opened in January 1846, but many problems both with the pumping equipment and in maintaining air-tight seals in the delivery pipes were encountered. The London and Croydon Railway became a part of the London Brighton and South Coast Railway in July 1846 and the new board of directors invited Samuda to operate the new atmospheric railway on their behalf in return for a fixed fee. Once further propulsion problems became apparent in the second section of line to be equipped, between Forest Hill
Forest Hill railway station
Forest Hill railway station is situated in Forest Hill, part of the London Borough of Lewisham. The station is located on the South Circular Road ....
and New Cross
New Cross Gate station
New Cross Gate station is a railway station in New Cross, London, on the Brighton Main Line. It is about 600 metres west of station. It is in Travelcard Zone 2, on the East London Line. The station is operated by London Overground.-History:...
, during 1847 the atmospheric method of propulsion was abandoned and the equipment sold.
One part of the pneumatic infrastructure was the viaduct from Sydenham to Crystal Palace, crossing the main lines. The pneumatic pipe could not cross the metals, so it was necessary to build a fly-over. This is reputed to be the first of its kind and is still in use today.
South Devon Railway
The extension of Brunel's broad gauge
Broad gauge
Broad-gauge railways use a track gauge greater than the standard gauge of .- List :For list see: List of broad gauges, by gauge and country- History :...
railway westward from Exeter towards Plymouth by the South Devon Railway Company
South Devon Railway Company
The South Devon Railway Company built and operated the railway from Exeter to Plymouth and Torquay in Devon, England. It was a broad gauge railway built by Isambard Kingdom Brunel-Chronology:* 1844 South Devon Railway Act passed by parliament...
(SDR) involved one of his most interesting uses of technical innovation. Brunel and others from the GWR travelled to Ireland to view the atmospheric system at Dalkey first hand. Afterwards Brunel's engineer of locomotives for the GWR, Daniel Gooch
Daniel Gooch
Sir Daniel Gooch, 1st Baronet was an English railway and transatlantic cable engineer and Conservative politician who sat in the House of Commons from 1865 to 1885...
, calculated that conventional locomotives could work the proposed Plymouth line at lower cost, but Brunel's concerns with the heavy grades led him to try the atmospheric system regardless.
The 20 miles (32.2 km) section from Exeter to Newton (now Newton Abbot
Newton Abbot
Newton Abbot is a market town and civil parish in the Teignbridge District of Devon, England on the River Teign, with a population of 23,580....
) was completed on the principle, with stationary engines at around 3 mi (5 km) intervals. Trains ran at speeds of up to 70 miles per hour (113 km/h), but service speeds were usually around 40 mph (64 km/h). The level portions used 15 inches (38 cm) pipes and the steeper gradients west of Newton were to have used 22 in (56 cm) pipes. It is not clear how the change between the two pipe sizes would have been achieved unless the piston carriages were changed at Newton. It is also unclear how the level crossing
Level crossing
A level crossing occurs where a railway line is intersected by a road or path onone level, without recourse to a bridge or tunnel. It is a type of at-grade intersection. The term also applies when a light rail line with separate right-of-way or reserved track crosses a road in the same fashion...
at Turf was operated as the pipe projected above the rails.
The harsh environment of the line, which runs next to the sea and is soaked with salt spray in even moderate winds, presented difficulties in maintaining the leather flaps provided to seal the vacuum pipes, which had to be kept supple by being greased
Grease (lubricant)
The term grease is used to describe semisolid lubricants. Although the word grease is also used to describe rendered fat of animals, in the context of lubrication, grease typically applies to a material consisting of a soap emulsified with mineral or vegetable oil...
with tallow
Tallow
Tallow is a rendered form of beef or mutton fat, processed from suet. It is solid at room temperature. Unlike suet, tallow can be stored for extended periods without the need for refrigeration to prevent decomposition, provided it is kept in an airtight container to prevent oxidation.In industry,...
; even so, air leaked in, destroying the vacuum. Unfortunately, the tallow made the greased leather attractive to rats
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
, whose depradations further reduced the efficiency of the seal.
Despite the building of several engine houses, the system never expanded beyond Newton. The proposal to use the same system on the Cornwall Railway
Cornwall Railway
The Cornwall Railway was a broad gauge railway from Plymouth in Devon to Falmouth in Cornwall, United Kingdom. The section from Plymouth to Truro opened in 1859, the extension to Falmouth in 1863...
was not pursued.
There are remains of several South Devon Railway engine houses
South Devon Railway engine houses
The South Devon Railway engine houses were built in Devon, England, to power the atmospheric trains on the South Devon Railway between Exeter St Davids and Plymouth Millbay railway stations. They contained boilers that provided the power to pumps that created the vacuum to move the trains...
, including one at Starcross
Starcross
Starcross is a riverside village with a population of 1,780, situated on the west bank of the estuary of the River Exe in Teignbridge in the English county of Devon...
, on the estuary of the River Exe
River Exe
The River Exe in England rises near the village of Simonsbath, on Exmoor in Somerset, near the Bristol Channel coast, but flows more or less directly due south, so that most of its length lies in Devon. It reaches the sea at a substantial ria, the Exe Estuary, on the south coast of Devon...
. It is a striking landmark and a reminder of the atmospheric railway, commemorated by the name of the village pub, the 'Atmospheric Railway'. A section of the pipe, without the leather covers, is preserved in Didcot Railway Centre.
Other early applications
- The Paris–Saint-Germain railway between Bois de Vésinet and Saint-Germain-en-LayeSaint-Germain-en-LayeSaint-Germain-en-Laye is a commune in the Yvelines department in the Île-de-France in north-central France. It is located in the western suburbs of Paris from the centre.Inhabitants are called Saint-Germanois...
, France (8.5 km (5.3 mi)) 1847–60
- Beach Pneumatic TransitBeach Pneumatic TransitThe Beach Pneumatic Transit was the first attempt to build an underground public transit system in New York City, USA.-History:In 1869, Alfred Ely Beach and his Beach Pneumatic Transit Company of New York began constructing a pneumatic subway line beneath Broadway...
One city block long subway beneath BroadwayBroadway (New York City)Broadway is a prominent avenue in New York City, United States, which runs through the full length of the borough of Manhattan and continues northward through the Bronx borough before terminating in Westchester County, New York. It is the oldest north–south main thoroughfare in the city, dating to...
in New York City,1870–73.
- The Crystal Palace atmospheric railway of 1864 had seals around the carriage, so (like RammellThomas Webster RammellThomas Webster Rammell was born in Dent de Lyon on the Isle of Thanet, Kent, United Kingdom. He became an engineer, working for the Metropolitan Board of Health...
's similar London Pneumatic Despatch CompanyLondon Pneumatic Despatch CompanyThe London Pneumatic Despatch Company was formed on 30 June 1859, to design, build and operate an underground railway system for the carrying of mail, parcels and light freight between locations in London...
) the whole carriage fits in a tube tunnel and was propelled by the large fixed fan.
Recent applications
The Aeromovel Corporation markets an automated people mover that is air driven. The elevated lightweight trains ride on a concrete box girder containing electric motors that drive air inside the girder, creating a constant airflow. Each car has a square plate protruding into the box girder. The plate is rotated into the airflow to catch the wind and accelerate the car.Systems have been built in Porto Alegre
Porto Alegre
Porto Alegre is the tenth most populous municipality in Brazil, with 1,409,939 inhabitants, and the centre of Brazil's fourth largest metropolitan area . It is also the capital city of the southernmost Brazilian state of Rio Grande do Sul. The city is the southernmost capital city of a Brazilian...
, Brazil (a two-station demonstration line) and in Taman Mini Indonesia Indah, Jakarta, Indonesia (a 2 miles (3 km) six-station loop serving a theme park).
A web page describing a system called 'Whoosh' was available for a time. The system is a single monorail track of the vacuum tube with a track either side. The piston in the tube is connected to the carriage below which is supported by wheels running on the tracks each side of the tube.
Advantages
The supporters of the atmospheric system claimed it had several advantages over traditional motive powerMotive power
In thermodynamics, motive power is an agency, as water or steam, used to impart motion. Generally, motive power is defined as a natural agent, as water, steam, wind, electricity, etc., used to impart motion to machinery; a motor; a mover. The term may also define something, as a locomotive or a...
by steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
.
- HillclimbingHillclimbing (railway)While railways have a great ability to haul very heavy loads, this advantage only really applies when the tracks are fairly level. As soon as the gradients stiffen, the tonnage that can be hauled is greatly diminished.- Techniques to overcome steep hills :...
ability. On the two longest-lived applications, at Dalkey and Saint-Germain, this seems to have been vindicated: the system was used on uphill journeys and gravity in the other direction. Brunel assumed that the system would work on the very challenging gradients of up to 1 in 38 on the PlymouthPlymouthPlymouth is a city and unitary authority area on the coast of Devon, England, about south-west of London. It is built between the mouths of the rivers Plym to the east and Tamar to the west, where they join Plymouth Sound...
main line if the South Devon application had been extended beyond Newton, probably by increasing the diameter of the tube on the gradients (although this would have involved a complex expanding piston arrangement); however here it was tested only on a relatively flat section. - Operating efficienciesPermanent wayThe permanent way is the elements of railway lines: generally the pairs of rails typically laid on the sleepers embedded in ballast, intended to carry the ordinary trains of a railway...
. Atmospheric railways could be operated on cheaper and lighter tracks which did not have to carry the weight of a locomotive, and could take advantage of sharper curves. - Fuel efficiencyFuel efficiencyFuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...
. It was far cheaper to maintain and operate a few large pumping engines than a large number of individual locomotives. - CleanlinessCleanlinessCleanliness is both the abstract state of being clean and free from dirt, and the process of achieving and maintaining that state.Cleanliness may be endowed with a moral quality, as indicated by the aphorism "cleanliness is next to godliness," and may be regarded as contributing to other ideals...
. The smoke and dirt from the steam engines was kept away from the passengers. - SafetySafetySafety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...
. The system could achieve higher speeds, but it would be impossible to operate two trains on the same stretch of track simultaneously and so collisions would be avoided.
Disadvantages
The failure of the system was due to technical problems with the stationary engines and the leather seals on the vacuum pipes. The former were suffered by the London and Croydon RailwayLondon and Croydon Railway
The London and Croydon Railway was an early railway which operated between London and Croydon in England. It was opened in 1839 and in July 1846 it merged with other railways to form a part of the London Brighton and South Coast Railway ....
but would have been overcome with more experience by the manufacturers and operators. The difficulty of maintaining an air-tight seal in the vacuum pipes was a serious problem, particularly for the South Devon Railway Company
South Devon Railway Company
The South Devon Railway Company built and operated the railway from Exeter to Plymouth and Torquay in Devon, England. It was a broad gauge railway built by Isambard Kingdom Brunel-Chronology:* 1844 South Devon Railway Act passed by parliament...
, which was never satisfactorily solved using the materials and technology of the 1840s.
The atmospheric system also suffered from a number of operating problems.
- ShuntingShunt (railway operations)Shunting, in railway operations, involves the process of sorting items of rolling stock into complete train sets or consists. The United States terminology is "switching"....
the trains into atmospheric formation was difficult or cumbersome (although this would have seemed less of a problem in an era when much shunting was carried out by horse- or man-power). - A change in traction, with consequent delays, would be necessary if an atmospheric line became part of a through route.
- There had to be gaps in the atmospheric tubes at pointsRailroad switchA railroad switch, turnout or [set of] points is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction....
, with flyoversOverpassAn overpass is a bridge, road, railway or similar structure that crosses over another road or railway...
or similar arrangements at junctions; and special arrangements would have been needed at level crossingLevel crossingA level crossing occurs where a railway line is intersected by a road or path onone level, without recourse to a bridge or tunnel. It is a type of at-grade intersection. The term also applies when a light rail line with separate right-of-way or reserved track crosses a road in the same fashion...
s.
Overall assessment
The atmospheric system foresaw the inherent efficiencies of delivering centrally generated power to the line side rather than generating it on individual locomotives, as would ultimately become the normal practice with electrification systemsRailway electrification system
A railway electrification system supplies electrical energy to railway locomotives and multiple units as well as trams so that they can operate without having an on-board prime mover. There are several different electrification systems in use throughout the world...
. The use of modern materials and technology would overcome many of the problems of the original systems, but atmospheric railways were ultimately too inflexible for widespread use.
See also
- Dalkey Atmospheric RailwayDalkey Atmospheric RailwayThe Dalkey Atmospheric Railway was an extension of the Dublin and Kingstown Railway to Atmospheric Road in Dalkey, Co. Dublin, Ireland. It used part of the Dalkey Quarry industrial tramway, which was earlier used for the construction of Kingstown Harbour...
- Beach Pneumatic TransitBeach Pneumatic TransitThe Beach Pneumatic Transit was the first attempt to build an underground public transit system in New York City, USA.-History:In 1869, Alfred Ely Beach and his Beach Pneumatic Transit Company of New York began constructing a pneumatic subway line beneath Broadway...
- Crystal Palace pneumatic railwayCrystal Palace pneumatic railwayThe Crystal Palace pneumatic railway was an experimental atmospheric railway constructed near Crystal Palace Park in South London c.1864.-History:...
- Cable railwayCable railwayA cable railway is a steeply graded railway that uses a cable or rope to haul trains.-Introduction:...
– a more successful albeit slow way of overcoming steep grades. - FunicularFunicularA funicular, also known as an inclined plane or cliff railway, is a cable railway in which a cable attached to a pair of tram-like vehicles on rails moves them up and down a steep slope; the ascending and descending vehicles counterbalance each other.-Operation:The basic principle of funicular...
– a system of overcoming steep grades using the force of gravity on downbound cars to raise upbound cars - Steam catapult – the arrangement of seal and traveller is essentially the same, albeit all steel.
- VactrainVactrainA vactrain is a proposed, as-yet-unbuilt design for future high-speed railroad transportation. This would entail building maglev lines through evacuated or partly evacuated tubes or tunnels...
– combination of gravity and air power