Tracked Hovercraft
Encyclopedia
Tracked Hovercraft was an experimental high speed train
developed in the United Kingdom
during the 1960s. It combined two British inventions, the hovercraft
and linear induction motor
, in an effort to produce a train system that would provide 250 mph inter-city service with lowered capital costs compared to other high-speed solutions. Substantially similar to the French Aérotrain
, Tracked Hovercraft suffered a similar fate when it was cancelled as a part of wide budget cuts in 1973.
that the energy needed to lift a vehicle was directly related to the smoothness of the surface it travelled on. This was not entirely surprising; the air trapped under the hovercraft's skirt will remain there except where it leaks out around the bottom where the lifting surface contacts the ground - if this interface is smooth, the amount of leaked air will be low. Early research focussed on marine applications, due to the hovercraft's excellent amphibious capabilities, which led to the introduction of the "skirt" to maintain as close a contact with bumpy surfaces.
What was a surprise was that the amount of energy needed to lift a given vehicle was lower than steel wheeled vehicles, at least at high speeds. Over 140 mph, conventional trains suffered from a problem known as hunting oscillation
that forces the flanges on the sides of the wheels to hit the rail with increasing frequency, dramatically increasing rolling resistance
. That meant that for travel above some critical speed, a hovercraft would be more efficient than a wheeled vehicle running on the same surface.
Better yet, this vehicle would also retain all of the positive qualities of a hovercraft. Small imperfections in the surface would have no effect on the ride quality, and the complexity of the suspension system could be greatly reduced. Additionally, since the load is spread out over the surface of the lifting pads, often the entire underside of the vehicle, the pressure on the running surface is greatly reduced - about 1/10,000 th the pressure of a train wheel, about 1/20 th of the pressure of a tyre on a road. These two properties meant that the running surface could be considerably simpler than the surface needed to support the same vehicle on wheels; hovertrain
s could be supported on surfaces similar to existing light-duty roadways, instead of the much more complex and expensive railbeds needed to support the weight on two rails. This could dramatically reduce infrastructure capital costs.
In 1960 several engineers at Christopher Cockerell
's Hovercraft Development Ltd. in Hythe, Kent
began early studies on the hovertrain
concept, but found no suitable driving power source. Since the entire concept relied on a hovering vehicle, there was almost no load for a wheel to work against. Propeller and jet engines were a possible solution, one that was tried by several other experimental systems over the years, but these were not nearly efficient as conventional engines.
had been developing the linear induction motor
(LIM) at the University of Manchester
. By 1961 he had built a small demonstration system consisting of a 20 feet (6.1 m) LIM reaction plate and a four-wheeled cart with a seat on top. In 1962 he started consulting with British Rail
(BR) on the idea of using LIMs for high-speed trains. A November 1961 Popular Science
article shows his Hovertrain concept using a LIM, it used small lift pads like those from the Ford Levapad concept, running on top of conventional rails. After moving to Imperial College London
in 1964, he was able to devote more time to this work and perfect the first working examples of large LIMs suitable for transport systems.
LIM's provide traction through the interaction of magnetic fields generated on the vehicle and a fixed external system. In most cases, the external portion is nothing more than a thin plate of metal, typically aluminium
due to its high magnetic susceptibility
in relation to its price. The active portion of the motor consists of a conventional electric motor
winding stretched out under the vehicle. When the motor windings are energized, an opposing magnetic field is induced in the nearby reaction plate, which causes the two to attract (or repel) each other. By moving the fields down the windings, the motor pushes itself along the plate with the same force that is normally used to create rotation in a conventional motor. A LIM eliminates the need for strong physical contact with the track, requiring instead a strong reaction plate, and has no moving parts, a major advantage over conventional traction. This work was picked up by most teams working on advanced transport systems.
As development of the testbed design continued at HDL, the problem of high-speed loads on the guideway became more obvious. In spite of its light weight compared to conventional railways, the Tracked Hovercraft operated at such high speeds that its passage induced vibration modes in the guideway that needed to be damped out. This was a relatively new field for the civil engineers
that were working on the guideway design, as their field was more generally concerned with static loads. The train layout was redesigned, with the top-mounted reaction plate being used for the LIM only, and the vertical sides of the box-like guideway being used for centring. Wing-like extensions extended down from the body of the train and covered the centring pads. A version with this layout was built as a scale model at Hythe, and featured in another Pathé film in 1966. This version was shown at Hovershow '66.
A further modification produced a guideway that looked like a rightside-up T, although the vertical section was a trapezoidal girder almost as wide as the top of the T. The reaction plate for the LIM was mounted to the underside of the horizontal portion of the T on one side, extending down, while the other side contained the electrical conductors that provided power. The new guideway design was simulated at the Atlas Computer Laboratory
. This work included the generation of films showing the vehicle in-action, using a Stromberg Carlson SC4020 microfilm recorder.
in Derby
. This work was the first to characterize the hunting oscillation in detail. It clearly suggested that, with careful design, the problem could be eliminated. This allowed high-speed trains to be built using conventional steel-wheel technology.
Although high speed travel would require new lines to be laid, expensive ones, such a train could use existing rail infrastructure at lower speeds, greatly reducing capital costs of bringing the service into cities. They also showed that the capital cost advantages of the hovertrain concept were offset by the higher vehicle costs; the tracked hovercraft concept made sense for a smaller number of vehicles or longer lines where the capital costs were concentrated in the tracks, but neither of these characterized BR's operations.
Meanwhile, having exhausted their abilities to research their vehicles using their small models, the Hovercraft Development team had been petitioning their parent organization, the National Research Development Corporation
(NRDC), for additional funding to build a full-sized test track. NDRC was unsuccessful in raising new capital from the government, and decided to put in £1 million from their own pre-assigned discretionary budget to start construction of a track, hoping that additional funding would be forthcoming from industry.
On 1 April 1967, Hovercraft Development was officially transferred to National Physical Laboratory. Seeking to protect their investment, and finding little external funding, the NRDC decided to spin off the hovertrain group as Tracked Hovercraft Ltd. They also decided to spool out the funding over four years, starting with a £1 million grant for a single prototype vehicle and a short portion of the test track. Although this funding was enough only for the first stage of a track, the NRDC suggested it would be quite useful for testing low speed intra-urban versions of the concept.
Frustrated with BR's lack of interest in his hovertrain work, and their lack of funding, in 1967 Laithwaite severed his ties with BR and joined Tracked Hovercraft as a consultant. By this time the French government had started providing major funding for Jean Bertin's Aérotrain
project, which was substantially similar to the Tracked Hovercraft concept. Laithwaite, always described as persuasive, convinced the government that they were about to lose out on this burgeoning field of high-speed transit, and eventually won £2 million in additional funding.
Most systems using LIMs -there were dozens by this point- redesigned their tracks to use a single-sided LIM over a stator plate lying flat between the rails. This led to another redesign of the guideway as a square box girder with the LIM stator attached flat on the top of the box, and the electrical pickups below on either side of it. Power pickups extended from the rear of the "wings", and the sparks they threw during operation are easily visible on test runs.
Starting in the 1970s, construction of test track started in the fens at Earith
in Cambridgeshire
. The track was about 6 feet off the ground, running along the north-western side of the Counter Drain that runs parallel to the Old Bedford River
between Earith and the Denver Sluice
. The first 4 mile long section of the planned 20 mile long track was laid to Sutton-in-the-Isle
. Along the full 20 mile length it was expected the train would reach 300 mph.
On 7 February 1973 the first test train, "Research Test Vehicle 31", or "RTV 31", reached 104 mph (167 km/h) on a 1 mile section, in spite of the short track and a 20 mph headwind. The test was heavily publicized and shown on BBC
news throughout the day. Much of the interest stemmed from rumours that the project was facing imminent cancellation. Aerospace Minister Michael Heseltine
sent Michael McNair-Wilson
to view the test, and when interviewed he stated his belief that the project would not be cancelled.
(APT). The government found itself in the position of funding two different high-speed train systems whose proponents were quick to point out problems in the competing system. To gain some clarity, they formed an interdepartmental working party that studied several potential inter-city transit solutions on the London-Manchester and London-Glasgow routes - buses, BR's APT, Tracked Hovercraft, and VTOL
and STOL
aircraft. Their December 1971 report strongly favoured APT.
Only a week after McNair-Wilson's comments at the run in February 1973, funding for the Tracked Hovercraft project was cancelled. Aerospace Minister Michael Heseltine noted problems with the concept, and stated that there was no prospect of a system being installed before 1985, and very limited possibilities between then and the end of the century. He stated that further funding, already to the tune of £5 million by this point, made no sense at that time. Work on the LIM would continue to be funded, however, and the Department of Trade and Industry signed a £500,000 contract with Hawker Siddeley to carry on LIM development.
Heseltine was accused by Airey Neave
and others of earlier misleading the House of Commons when he stated that the government was still considering giving financial support to the hovertrain, when the decision to pull the plug must have already been taken by the Cabinet. He called together the Select Committee on Science and Technology to examine the issue, but they were constantly frustrated in their efforts to obtain cabinet meeting reports. One thing that did surface was that Hawker Siddeley and Tracked Hovercraft were in the process of entering a bid for the GO-Urban
system in Toronto
, and it was suggested that the LIM contract with Hawker was actually a grant so that proposal could be completed. The GO-Urban contest was eventually won by a low-speed maglev, the Krauss-Maffei Transurban
, a choice that occurred while the Committee was meeting.
Laithwaite was as publicly critical of the government's cancellation as he had been of BR's earlier efforts on LIM research. However, by this time he had distanced himself from the hovercraft arrangement, concluding that the maglev was a better solution. Laithwaite had found that careful arrangement of the LIM allowed a single motor to act as both the lift and traction system, a system he called "traverse-flux", or "river of magnetism". Having continued his research at Derby throughout, when it became clear that Tracked Hovercraft was truly dead, Laithwaite started pushing for the test track to be converted to a testbed for his maglev design. By that point Rohr, Inc.
in the U.S. were already experimenting with their own LIM arrangement of this sort on their ROMAG
personal rapid transport system, and there were several German maglev efforts underway as well. In the end the test track was abandoned, but Laithwaite's work would eventually be used as the basis for the Birmingham Maglev, the first operational maglev system.
where it was kept in the open for more than 20 years. In 1996 it was donated to Railworld
, where it was later restored and set up as a main display in front of the buildings. The test track was removed, but several concrete footings project at the ground level from a small pond beside the Counter Drain. The course of the track itself can be seen in aerial photography, as it has been re-used as a dirt road.
Many original documents from the Tracked Hovercraft project are stored within the Hovercraft Museum
library in Hampshire
, England
, including technical documents, video footage reels, press books and blueprints. A scale model of the RTV 31, a working miniature LIM, photographs, video footage and archive documents are kept within the Hovercraft Museum
. Another scale model of the RTV 31 is kept within the Railworld
museum.
High Speed Train
There are three types of trains in Britain that have been traditionally viewed as high speed trains:* Advanced Passenger Train - Tilting trains which never entered into regular revenue-earning service....
developed in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
during the 1960s. It combined two British inventions, the hovercraft
Hovercraft
A hovercraft is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a "skirt." Although supported by air, a hovercraft is not considered an aircraft.Hovercraft are used throughout...
and linear induction motor
Linear induction motor
A linear induction motor is an AC asynchronous linear motor that works by the same general principles as other induction motors but which has been designed to directly produce motion in a straight line....
, in an effort to produce a train system that would provide 250 mph inter-city service with lowered capital costs compared to other high-speed solutions. Substantially similar to the French Aérotrain
Aérotrain
The Aérotrain was a Hovertrain developed in France from 1965 to 1977. The lead engineer was Jean Bertin.The goal of the Aérotrain was similar to that of the magnetic levitation train: to suspend the train above the tracks so the only resistance is that of air resistance...
, Tracked Hovercraft suffered a similar fate when it was cancelled as a part of wide budget cuts in 1973.
Genesis at Hovercraft Development
It was noticed early on in the development of the hovercraftHovercraft
A hovercraft is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a "skirt." Although supported by air, a hovercraft is not considered an aircraft.Hovercraft are used throughout...
that the energy needed to lift a vehicle was directly related to the smoothness of the surface it travelled on. This was not entirely surprising; the air trapped under the hovercraft's skirt will remain there except where it leaks out around the bottom where the lifting surface contacts the ground - if this interface is smooth, the amount of leaked air will be low. Early research focussed on marine applications, due to the hovercraft's excellent amphibious capabilities, which led to the introduction of the "skirt" to maintain as close a contact with bumpy surfaces.
What was a surprise was that the amount of energy needed to lift a given vehicle was lower than steel wheeled vehicles, at least at high speeds. Over 140 mph, conventional trains suffered from a problem known as hunting oscillation
Hunting oscillation
Hunting oscillation is an oscillation, usually unwanted, about an equilibrium. The expression came into use in the 19th century and describes how a systems 'hunts' for equilibrium...
that forces the flanges on the sides of the wheels to hit the rail with increasing frequency, dramatically increasing rolling resistance
Rolling resistance
Rolling resistance, sometimes called rolling friction or rolling drag, is the resistance that occurs when a round object such as a ball or tire rolls on a flat surface, in steady velocity straight line motion. It is caused mainly by the deformation of the object, the deformation of the surface, or...
. That meant that for travel above some critical speed, a hovercraft would be more efficient than a wheeled vehicle running on the same surface.
Better yet, this vehicle would also retain all of the positive qualities of a hovercraft. Small imperfections in the surface would have no effect on the ride quality, and the complexity of the suspension system could be greatly reduced. Additionally, since the load is spread out over the surface of the lifting pads, often the entire underside of the vehicle, the pressure on the running surface is greatly reduced - about 1/10,000 th the pressure of a train wheel, about 1/20 th of the pressure of a tyre on a road. These two properties meant that the running surface could be considerably simpler than the surface needed to support the same vehicle on wheels; hovertrain
Hovertrain
A hovertrain is a type of high-speed train that replaces conventional steel wheels with hovercraft lift pads, and the conventional railway bed with a paved road-like surface, known as the "track" or "guideway"...
s could be supported on surfaces similar to existing light-duty roadways, instead of the much more complex and expensive railbeds needed to support the weight on two rails. This could dramatically reduce infrastructure capital costs.
In 1960 several engineers at Christopher Cockerell
Christopher Cockerell
Sir Christopher Sydney Cockerell CBE FRS was an English engineer, inventor of the hovercraft.-Life:Cockerell was born in Cambridge, where his father, Sir Sydney Cockerell, was curator of the Fitzwilliam Museum, having previously been the secretary of William Morris. Christopher Cockerell was...
's Hovercraft Development Ltd. in Hythe, Kent
Hythe, Kent
Hythe , is a small coastal market town on the edge of Romney Marsh, in the District of Shepway on the south coast of Kent. The word Hythe or Hithe is an Old English word meaning Haven or Landing Place....
began early studies on the hovertrain
Hovertrain
A hovertrain is a type of high-speed train that replaces conventional steel wheels with hovercraft lift pads, and the conventional railway bed with a paved road-like surface, known as the "track" or "guideway"...
concept, but found no suitable driving power source. Since the entire concept relied on a hovering vehicle, there was almost no load for a wheel to work against. Propeller and jet engines were a possible solution, one that was tried by several other experimental systems over the years, but these were not nearly efficient as conventional engines.
Introducing the LIM
Through the same period, Eric LaithwaiteEric Laithwaite
Eric Roberts Laithwaite was a British electrical engineer, known as the "Father of Maglev" for his development of the linear induction motor and maglev rail system.- Biography :...
had been developing the linear induction motor
Linear induction motor
A linear induction motor is an AC asynchronous linear motor that works by the same general principles as other induction motors but which has been designed to directly produce motion in a straight line....
(LIM) at the University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
. By 1961 he had built a small demonstration system consisting of a 20 feet (6.1 m) LIM reaction plate and a four-wheeled cart with a seat on top. In 1962 he started consulting with British Rail
British Rail
British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...
(BR) on the idea of using LIMs for high-speed trains. A November 1961 Popular Science
Popular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...
article shows his Hovertrain concept using a LIM, it used small lift pads like those from the Ford Levapad concept, running on top of conventional rails. After moving to Imperial College London
Imperial College London
Imperial College London is a public research university located in London, United Kingdom, specialising in science, engineering, business and medicine...
in 1964, he was able to devote more time to this work and perfect the first working examples of large LIMs suitable for transport systems.
LIM's provide traction through the interaction of magnetic fields generated on the vehicle and a fixed external system. In most cases, the external portion is nothing more than a thin plate of metal, typically aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
due to its high magnetic susceptibility
Magnetic susceptibility
In electromagnetism, the magnetic susceptibility \chi_m is a dimensionless proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field...
in relation to its price. The active portion of the motor consists of a conventional electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
winding stretched out under the vehicle. When the motor windings are energized, an opposing magnetic field is induced in the nearby reaction plate, which causes the two to attract (or repel) each other. By moving the fields down the windings, the motor pushes itself along the plate with the same force that is normally used to create rotation in a conventional motor. A LIM eliminates the need for strong physical contact with the track, requiring instead a strong reaction plate, and has no moving parts, a major advantage over conventional traction. This work was picked up by most teams working on advanced transport systems.
Hovertrain
The Hovercraft Development team quickly picked up on the LIM concept as well. Their initial solution was a track shaped like an upside-down "T", with the vertical portion consisting of a central concrete section with aluminium "stators" fixed on either side. This allowed the winding on the vehicle to be placed on either side of the stator, clamped together to keep the forces internalized to the motor. Their first train design looked like the fuselage of an airliner with two decks, riding above the stator beam, with the LIM centred in the middle of the body. Four pads provided lift, arranged two on a side fore and aft and riding on the horizontal surface of the guideway. Four more pads, above the lift pads, were turned vertically and pressed against the centre beam to kept the craft centred. A test rig of this layout was built at Hythe, which was filmed in operation by British Pathé in 1963, which also showed a model of the proposed full-sized version.As development of the testbed design continued at HDL, the problem of high-speed loads on the guideway became more obvious. In spite of its light weight compared to conventional railways, the Tracked Hovercraft operated at such high speeds that its passage induced vibration modes in the guideway that needed to be damped out. This was a relatively new field for the civil engineers
Civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...
that were working on the guideway design, as their field was more generally concerned with static loads. The train layout was redesigned, with the top-mounted reaction plate being used for the LIM only, and the vertical sides of the box-like guideway being used for centring. Wing-like extensions extended down from the body of the train and covered the centring pads. A version with this layout was built as a scale model at Hythe, and featured in another Pathé film in 1966. This version was shown at Hovershow '66.
A further modification produced a guideway that looked like a rightside-up T, although the vertical section was a trapezoidal girder almost as wide as the top of the T. The reaction plate for the LIM was mounted to the underside of the horizontal portion of the T on one side, extending down, while the other side contained the electrical conductors that provided power. The new guideway design was simulated at the Atlas Computer Laboratory
Atlas Computer Laboratory
The Atlas Computer Laboratory on the Chilton, Oxfordshire campus shared by the Harwell Laboratory was one of the major computer laboratories in the world, which operated between 1961 and 1975 to provide a service to British scientists at a time when powerful computers were not usually available...
. This work included the generation of films showing the vehicle in-action, using a Stromberg Carlson SC4020 microfilm recorder.
Laithwaite joins
While the hovertrain was being developed, BR was running an extensive research project on the topic of high-speed wheeled trains at their newly opened British Rail Research DivisionBritish Rail Research Division
The British Rail Research Division came into being in 1964 directly under the control of the British Railways Board, moving into purpose-built premises at the Railway Technical Centre in Derby. The intention was to improve railway reliability and efficiency, while reducing costs and improving revenue...
in Derby
Derby
Derby , is a city and unitary authority in the East Midlands region of England. It lies upon the banks of the River Derwent and is located in the south of the ceremonial county of Derbyshire. In the 2001 census, the population of the city was 233,700, whilst that of the Derby Urban Area was 229,407...
. This work was the first to characterize the hunting oscillation in detail. It clearly suggested that, with careful design, the problem could be eliminated. This allowed high-speed trains to be built using conventional steel-wheel technology.
Although high speed travel would require new lines to be laid, expensive ones, such a train could use existing rail infrastructure at lower speeds, greatly reducing capital costs of bringing the service into cities. They also showed that the capital cost advantages of the hovertrain concept were offset by the higher vehicle costs; the tracked hovercraft concept made sense for a smaller number of vehicles or longer lines where the capital costs were concentrated in the tracks, but neither of these characterized BR's operations.
Meanwhile, having exhausted their abilities to research their vehicles using their small models, the Hovercraft Development team had been petitioning their parent organization, the National Research Development Corporation
National Research Development Corporation
The National Research Development Corporation was a non-departmental government body established by the British Government to transfer technology from the public sector to the private sector.-History:...
(NRDC), for additional funding to build a full-sized test track. NDRC was unsuccessful in raising new capital from the government, and decided to put in £1 million from their own pre-assigned discretionary budget to start construction of a track, hoping that additional funding would be forthcoming from industry.
On 1 April 1967, Hovercraft Development was officially transferred to National Physical Laboratory. Seeking to protect their investment, and finding little external funding, the NRDC decided to spin off the hovertrain group as Tracked Hovercraft Ltd. They also decided to spool out the funding over four years, starting with a £1 million grant for a single prototype vehicle and a short portion of the test track. Although this funding was enough only for the first stage of a track, the NRDC suggested it would be quite useful for testing low speed intra-urban versions of the concept.
Frustrated with BR's lack of interest in his hovertrain work, and their lack of funding, in 1967 Laithwaite severed his ties with BR and joined Tracked Hovercraft as a consultant. By this time the French government had started providing major funding for Jean Bertin's Aérotrain
Aérotrain
The Aérotrain was a Hovertrain developed in France from 1965 to 1977. The lead engineer was Jean Bertin.The goal of the Aérotrain was similar to that of the magnetic levitation train: to suspend the train above the tracks so the only resistance is that of air resistance...
project, which was substantially similar to the Tracked Hovercraft concept. Laithwaite, always described as persuasive, convinced the government that they were about to lose out on this burgeoning field of high-speed transit, and eventually won £2 million in additional funding.
RTV 31
By the time construction was preparing to start in 1970, a new problem had appeared. Prior to construction most LIMs were test systems that had operated at low speeds, but as the speeds increased it was noticed that the mechanical forces of the LIM windings on the stator plate caused a compression wave to run down it. During rapid deceleration it was possible that the wave could move forward and become trapped in the LIM itself, causing catastrophic failures. Additionally, the passing of the train heated the plate, potentially weakening it mechanically. Laithwaite concluded that the double-sided LIM was "far too dangerous" to use.Most systems using LIMs -there were dozens by this point- redesigned their tracks to use a single-sided LIM over a stator plate lying flat between the rails. This led to another redesign of the guideway as a square box girder with the LIM stator attached flat on the top of the box, and the electrical pickups below on either side of it. Power pickups extended from the rear of the "wings", and the sparks they threw during operation are easily visible on test runs.
Starting in the 1970s, construction of test track started in the fens at Earith
Earith
Earith is a village in the Fens of Cambridgeshire, England, south of Chatteris and east of Huntingdon. At Earith, two artificial diversion channels of the River Great Ouse, the Old Bedford River and the New Bedford River, leave the river on a course to Denver Sluice near Downham Market, where they...
in Cambridgeshire
Cambridgeshire
Cambridgeshire is a county in England, bordering Lincolnshire to the north, Norfolk to the northeast, Suffolk to the east, Essex and Hertfordshire to the south, and Bedfordshire and Northamptonshire to the west...
. The track was about 6 feet off the ground, running along the north-western side of the Counter Drain that runs parallel to the Old Bedford River
Old Bedford River
The Old Bedford River is an artificial, partial diversion of the waters of the River Great Ouse in the Fens of Cambridgeshire, England. It was named after the fourth Earl of Bedford who contracted with the local Commission of Sewers to drain the Great Level of the Fens beginning in 1630.The idea of...
between Earith and the Denver Sluice
Denver, Norfolk
Denver is a village and civil parish in the English county of Norfolk. It is located on the River Great Ouse, 1 mile south of the small town of Downham Market, 14 miles south of the larger town of King's Lynn, and 37 miles west of the city of Norwich.The civil parish has an area of...
. The first 4 mile long section of the planned 20 mile long track was laid to Sutton-in-the-Isle
Sutton-in-the-Isle
Sutton-in-the-Isle, commonly referred to simply as Sutton, is a parish and village in the county of Cambridgeshire in England, near the city of Ely. The "in-the-Isle" suffix refers to the fact that the village is part of the Isle of Ely, once an island in The Fens and also an administrative county...
. Along the full 20 mile length it was expected the train would reach 300 mph.
On 7 February 1973 the first test train, "Research Test Vehicle 31", or "RTV 31", reached 104 mph (167 km/h) on a 1 mile section, in spite of the short track and a 20 mph headwind. The test was heavily publicized and shown on BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
news throughout the day. Much of the interest stemmed from rumours that the project was facing imminent cancellation. Aerospace Minister Michael Heseltine
Michael Heseltine
Michael Ray Dibdin Heseltine, Baron Heseltine, CH, PC is a British businessman, Conservative politician and patron of the Tory Reform Group. He was a Member of Parliament from 1966 to 2001 and was a prominent figure in the governments of Margaret Thatcher and John Major...
sent Michael McNair-Wilson
Michael McNair-Wilson
Sir Robert Michael Conal McNair-Wilson was a Conservative politician and a Member of Parliament .In 1969 he stood as the Conservative candidate in the Walthamstow East by-election, defeating the Labour Party...
to view the test, and when interviewed he stated his belief that the project would not be cancelled.
Cancellation
By the time construction started on Tracked Hovercraft's test track, British Rail was well advanced on their plans for the steel-wheeled Advanced Passenger TrainAdvanced Passenger Train
The Advanced Passenger Train was an experimental tilting High Speed Train developed by British Rail during the 1970s and early 1980s....
(APT). The government found itself in the position of funding two different high-speed train systems whose proponents were quick to point out problems in the competing system. To gain some clarity, they formed an interdepartmental working party that studied several potential inter-city transit solutions on the London-Manchester and London-Glasgow routes - buses, BR's APT, Tracked Hovercraft, and VTOL
VTOL
A vertical take-off and landing aircraft is one that can hover, take off and land vertically. This classification includes fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, such as cyclogyros/cyclocopters and tiltrotors...
and STOL
STOL
STOL is an acronym for short take-off and landing, a term used to describe aircraft with very short runway requirements.-Definitions:There is no one accepted definition of STOL and many different definitions have been used by different authorities and nations at various times and for a myriad of...
aircraft. Their December 1971 report strongly favoured APT.
Only a week after McNair-Wilson's comments at the run in February 1973, funding for the Tracked Hovercraft project was cancelled. Aerospace Minister Michael Heseltine noted problems with the concept, and stated that there was no prospect of a system being installed before 1985, and very limited possibilities between then and the end of the century. He stated that further funding, already to the tune of £5 million by this point, made no sense at that time. Work on the LIM would continue to be funded, however, and the Department of Trade and Industry signed a £500,000 contract with Hawker Siddeley to carry on LIM development.
Heseltine was accused by Airey Neave
Airey Neave
Airey Middleton Sheffield Neave DSO, OBE, MC was a British soldier, barrister and politician.During World War II, Neave was one of the few servicemen to escape from the German prisoner-of-war camp Oflag IV-C at Colditz Castle...
and others of earlier misleading the House of Commons when he stated that the government was still considering giving financial support to the hovertrain, when the decision to pull the plug must have already been taken by the Cabinet. He called together the Select Committee on Science and Technology to examine the issue, but they were constantly frustrated in their efforts to obtain cabinet meeting reports. One thing that did surface was that Hawker Siddeley and Tracked Hovercraft were in the process of entering a bid for the GO-Urban
GO-Urban
GO-Urban was a major mass transit project planned for the Toronto area which would have been run by GO Transit. The system envisioned the use of automated guideway transit vehicles set up in hydro corridors and other unused parcels of land to provide rapid transit services without the expense of...
system in Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
, and it was suggested that the LIM contract with Hawker was actually a grant so that proposal could be completed. The GO-Urban contest was eventually won by a low-speed maglev, the Krauss-Maffei Transurban
Krauss-Maffei Transurban
Krauss-Maffei's Transurban was a 12-passenger automated guideway transit mass transit system based on a maglev guideway. Development started in 1970 as one of the many AGT and PRT projects that followed in the wake of the HUD reports of 1968...
, a choice that occurred while the Committee was meeting.
Laithwaite was as publicly critical of the government's cancellation as he had been of BR's earlier efforts on LIM research. However, by this time he had distanced himself from the hovercraft arrangement, concluding that the maglev was a better solution. Laithwaite had found that careful arrangement of the LIM allowed a single motor to act as both the lift and traction system, a system he called "traverse-flux", or "river of magnetism". Having continued his research at Derby throughout, when it became clear that Tracked Hovercraft was truly dead, Laithwaite started pushing for the test track to be converted to a testbed for his maglev design. By that point Rohr, Inc.
Rohr, Inc.
Goodrich Aerostructures Group, formerly Rohr, Inc., is an aerospace manufacturing company based in Chula Vista, California, south of San Diego...
in the U.S. were already experimenting with their own LIM arrangement of this sort on their ROMAG
ROMAG
ROMAG was a personal rapid transit system produced by the American company Rohr, Inc. It featured a linear induction motor that was arranged to provide both traction and suspension in a magnetic levitation system....
personal rapid transport system, and there were several German maglev efforts underway as well. In the end the test track was abandoned, but Laithwaite's work would eventually be used as the basis for the Birmingham Maglev, the first operational maglev system.
Fate
RTV 31 ended up at Cranfield UniversityCranfield University
Cranfield University is a British postgraduate university based on two campuses, with a research-oriented focus. The main campus is at Cranfield, Bedfordshire and the second is the Defence Academy of the United Kingdom based at Shrivenham, Oxfordshire. The main campus is unique in the United...
where it was kept in the open for more than 20 years. In 1996 it was donated to Railworld
Railworld
Railworld is a railway museum in Peterborough.http://www.railworld.net/ It is located beside the Peterborough Nene Valley railway station but it is a separate organisation.-Exhibits:Alco switcher...
, where it was later restored and set up as a main display in front of the buildings. The test track was removed, but several concrete footings project at the ground level from a small pond beside the Counter Drain. The course of the track itself can be seen in aerial photography, as it has been re-used as a dirt road.
Many original documents from the Tracked Hovercraft project are stored within the Hovercraft Museum
Hovercraft Museum
The Hovercraft Museum, located in Lee-on-the-Solent in Hampshire, England, is dedicated to hovercraft.The museum has a large collection of various designs of hovercraft - numbering over sixty at the last count...
library in Hampshire
Hampshire
Hampshire is a county on the southern coast of England in the United Kingdom. The county town of Hampshire is Winchester, a historic cathedral city that was once the capital of England. Hampshire is notable for housing the original birthplaces of the Royal Navy, British Army, and Royal Air Force...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, including technical documents, video footage reels, press books and blueprints. A scale model of the RTV 31, a working miniature LIM, photographs, video footage and archive documents are kept within the Hovercraft Museum
Hovercraft Museum
The Hovercraft Museum, located in Lee-on-the-Solent in Hampshire, England, is dedicated to hovercraft.The museum has a large collection of various designs of hovercraft - numbering over sixty at the last count...
. Another scale model of the RTV 31 is kept within the Railworld
Railworld
Railworld is a railway museum in Peterborough.http://www.railworld.net/ It is located beside the Peterborough Nene Valley railway station but it is a separate organisation.-Exhibits:Alco switcher...
museum.
Further reading
- Dennis Bliss, "The Tracked Hovercraft System of High Speed Land Transport", Railway Age, Proceedings [of the] annual meeting, Volume 8, pg. 333-359
- "How tracked hovercraft went off the rails", Industrial Management & Data Systems, Volume 79 Issue 8 (1979), pg. 14-15