Stud contact system
Encyclopedia
The Stud Contact System is a once-obsolete ground-level power supply
system for electric tram
s. Power supply studs were set in the road at intervals and connected to a buried electric cable by switches operated by magnets on the tramcars. Current was collected from the studs by a "skate" or "ski collector" under the tramcar. The system was popular for a while in the early 1900s but soon fell out of favour because of the unreliability of the magnetic switches. However, the new tram system in Bordeaux
, France
has resurrected the system in the form of alimentation par sol
for aesthetic reasons in the city centre.
In recent years the concept has made a comeback, to remove overhead supply systems from scenically sensitive areas. Current manufacturing methods and electronic control means such systems are much more reliable.
The stud contact system or surface contact system was used with some tramway
systems. It is used especially where an overhead system would be obtrusive. As the studs would be on open roads rather than special track, methods have to be adopted to ensure that they are only live when under a vehicle. Early systems used mechanical switches. Most use magnetic activation from a magnet on the vehicle, but a few used a purely mechanical system. Systems in use in the early part of the 20th century included: The Lorain, the Dolter, and the GB surface-contact systems, which were all magnetically operated,and the Robrow surface-contact system which was mechanical. In practice the technology of the time could be erratic. This meant studs that that did not make contact when activated, and studs that remain live after the vehicle had passed over. Consequently the systems tended to be replaced with either overhead systems, on continuous contact sub surface systems.
Most electric railway systems take the power from an external generator
. This means the electricity
has to be collected while the locomotive
is on the move. In this context a locomotive refers to any electric vehicle
on a guided track system. Other than railways the other most common system of electrically powered guided transport is a tramway
system.
Generally electric locomotives collect power through a third rail or an overhead wire. The full circuit is completed by track rails. For main line railways with their protected lines overhead lines and third rails are not a problem. Tramways operate in cities. This means that the third rail system is not really practical. It has been used, protection being offered to other road users by placing it in a central groove
. Even so the ingress of dirt and water can cause problems. An alternative solution is to use studs. These require a long collector under the locomotive, called a ski collector. So that the collector is always connected to the system the ski must be longer than the maximum distance between any two studs. Of course studs on the surface are live so all the systems have a switch in the stud and a means to switch on the stud only while it is covered by the moving vehicle.
Power supply studs with ski collectors have are also used on model railway systems, originally to be less obtrusive than a third rail system, but more recently on outdoor garden systems because the system has inherent self cleaning properties.
Instead of a third rail, studs are used to provide the power supply to some electric railway systems. As at least one stud must be covered by the collector at all times a long collector is used. The length be slightly greater than the maximum distance between any two studs. This collector is known as a skate or ski collector.
It is used on some full size tramway systems where there is a need for overhead wires not to be used. Usually in areas of scenic value. It is also used on model railway systems as the center line of studs is less obtrusive than a single central rail. For outdoor model railway systems the use of a stud supply system with a skate/ski collector has certain practical advantages. The system is inherently self cleaning. While the track may not be perfect, with both rails acting as the return part of the system in parallel electrical pick up problems are substantially reduced.
This is an electrical power collector used on stud contact electrification systems. It is also referred to as a skate or ski collector. It is a flat plate slightly longer than the maximum distance between any two studs. This ensures that at all times the collection is in contact with at least one stud. This type of electrical power collector needs to move in the vertical plane to allow for natural differences in the height of the power supply studs.
While the obvious use is on railway power collection, the system also has applications wherever electrical energy needs to be transferred from a static source to moving user, or vice versa.
, with over 20,000 studs in use. It was invented by an Italian, Alfredo Diatto of Turin
and was first installed in Tours
in 1899, followed by four of the Paris
tramway companies in 1900.
. A magnet on a passing tram attracted this crank which then moved to make contact between the conductor cable and stud; once the tram moved away the crank dropped away and the stud was no longer connected to the cable. A long skate was suspended beneath each tramcar which was magnetised by electro-magnets and so both operated the cranks and collected the current that both moved the tram car and powered the electro-magnets. A small battery was carried to charge the electro-magnets should the power be interrupted. The negative return current passed through the rails.
The town council of Torquay did not want their seaside resort disfigured by the poles and overhead wires of a conventional electric tramway and so invited the Dolter Electric Traction Company to construct a tramway using their stud-contact system. A horse was killed after it stepped on a live stud during construction of the Torquay Tramways
. Each tram car was then fitted with a bell connected to a special contact arm to warn the driver if a stud remained live after it had passed. The conductor of the tram then had to reset the crank using an insulated mallet. During the Board of Trade
inspection of the tramway four such studs were detected during about 8 miles (12.9 km) of tests. There were also frequent problems with trams being stopped when a stud failed to be made live when needed. The network covered 6.79 miles (10.9 km) and opened in stages during 1907 and 1908. On 27 January 1910 a snow storm stopped all the trams as they couldn't make contact with the studs. It was converted to overhead collection in 1911 shortly before it was extended to Paignton
where the town council had refused to allow the Dolter system to be used.
A short Dolter system also opened in 1907 in Hastings
along the seafront to connect two sections of a network that otherwise used overhead collection. It lasted until 1913. For the next eight years the trams that worked along Hastings sea front were fitted with a small motor to enable them to move between the two sections of overhead wire, but in 1921 wires were provided along the section.
The Mexborough & Swinton Tramway
used the Dolter system from 1907 until 1908 when it was converted to overhead supply.
Ground-level power supply
Ground-level power supply, also known as surface current collection and Alimentation par Sol is a modern method of third-rail electrical pick-up for street trams. It was invented for the Bordeaux tramway, which was constructed from 2000 and opened in 2003. Until 2011, this is the only place it is...
system for electric tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...
s. Power supply studs were set in the road at intervals and connected to a buried electric cable by switches operated by magnets on the tramcars. Current was collected from the studs by a "skate" or "ski collector" under the tramcar. The system was popular for a while in the early 1900s but soon fell out of favour because of the unreliability of the magnetic switches. However, the new tram system in Bordeaux
Tramway de Bordeaux
The Bordeaux tramway network consists of three lines serving the city of Bordeaux in southwestern France. The first line was opened on 21 December 2003; further extensions have increased the route length to . The system is notable for using a ground-level power supply of the Alimentation par Sol...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
has resurrected the system in the form of alimentation par sol
Ground-level power supply
Ground-level power supply, also known as surface current collection and Alimentation par Sol is a modern method of third-rail electrical pick-up for street trams. It was invented for the Bordeaux tramway, which was constructed from 2000 and opened in 2003. Until 2011, this is the only place it is...
for aesthetic reasons in the city centre.
In recent years the concept has made a comeback, to remove overhead supply systems from scenically sensitive areas. Current manufacturing methods and electronic control means such systems are much more reliable.
Studs
Power supply studs are the fixed contact elements of a stud/skate or stud/ski collector electrical connection system. They are used when a moving element needs to be in electrical contact with a static element. The main advantage of the system is the self cleaning facility of the skate/ski with the stud.The stud contact system or surface contact system was used with some tramway
Tramway
Tramway may refer to:* Tramway , a lightly laid railway for uses such as logging or mining * A system of trams * Aerial tramway...
systems. It is used especially where an overhead system would be obtrusive. As the studs would be on open roads rather than special track, methods have to be adopted to ensure that they are only live when under a vehicle. Early systems used mechanical switches. Most use magnetic activation from a magnet on the vehicle, but a few used a purely mechanical system. Systems in use in the early part of the 20th century included: The Lorain, the Dolter, and the GB surface-contact systems, which were all magnetically operated,and the Robrow surface-contact system which was mechanical. In practice the technology of the time could be erratic. This meant studs that that did not make contact when activated, and studs that remain live after the vehicle had passed over. Consequently the systems tended to be replaced with either overhead systems, on continuous contact sub surface systems.
Collectors
A ski collector is a long conductive plate under a vehicle, which connects to a series of separated studs to collect electricity to power the vehicle.Most electric railway systems take the power from an external generator
Electrical generator
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...
. This means the electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
has to be collected while the locomotive
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...
is on the move. In this context a locomotive refers to any electric vehicle
Electric vehicle
An electric vehicle , also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion...
on a guided track system. Other than railways the other most common system of electrically powered guided transport is a tramway
Tramway
Tramway may refer to:* Tramway , a lightly laid railway for uses such as logging or mining * A system of trams * Aerial tramway...
system.
Generally electric locomotives collect power through a third rail or an overhead wire. The full circuit is completed by track rails. For main line railways with their protected lines overhead lines and third rails are not a problem. Tramways operate in cities. This means that the third rail system is not really practical. It has been used, protection being offered to other road users by placing it in a central groove
Conduit current collection
Conduit current collection is a system of electric current collection used by electric trams, where the power supply is carried in a channel under the roadway, rather than located overhead.-Description:...
. Even so the ingress of dirt and water can cause problems. An alternative solution is to use studs. These require a long collector under the locomotive, called a ski collector. So that the collector is always connected to the system the ski must be longer than the maximum distance between any two studs. Of course studs on the surface are live so all the systems have a switch in the stud and a means to switch on the stud only while it is covered by the moving vehicle.
Power supply studs with ski collectors have are also used on model railway systems, originally to be less obtrusive than a third rail system, but more recently on outdoor garden systems because the system has inherent self cleaning properties.
Instead of a third rail, studs are used to provide the power supply to some electric railway systems. As at least one stud must be covered by the collector at all times a long collector is used. The length be slightly greater than the maximum distance between any two studs. This collector is known as a skate or ski collector.
It is used on some full size tramway systems where there is a need for overhead wires not to be used. Usually in areas of scenic value. It is also used on model railway systems as the center line of studs is less obtrusive than a single central rail. For outdoor model railway systems the use of a stud supply system with a skate/ski collector has certain practical advantages. The system is inherently self cleaning. While the track may not be perfect, with both rails acting as the return part of the system in parallel electrical pick up problems are substantially reduced.
This is an electrical power collector used on stud contact electrification systems. It is also referred to as a skate or ski collector. It is a flat plate slightly longer than the maximum distance between any two studs. This ensures that at all times the collection is in contact with at least one stud. This type of electrical power collector needs to move in the vertical plane to allow for natural differences in the height of the power supply studs.
While the obvious use is on railway power collection, the system also has applications wherever electrical energy needs to be transferred from a static source to moving user, or vice versa.
Diatto
The Diatto stud system was the most common in FranceFrance
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, with over 20,000 studs in use. It was invented by an Italian, Alfredo Diatto of Turin
Turin
Turin is a city and major business and cultural centre in northern Italy, capital of the Piedmont region, located mainly on the left bank of the Po River and surrounded by the Alpine arch. The population of the city proper is 909,193 while the population of the urban area is estimated by Eurostat...
and was first installed in Tours
Tours
Tours is a city in central France, the capital of the Indre-et-Loire department.It is located on the lower reaches of the river Loire, between Orléans and the Atlantic coast. Touraine, the region around Tours, is known for its wines, the alleged perfection of its local spoken French, and for the...
in 1899, followed by four of the Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
tramway companies in 1900.
Dolter
For the Dolter system a conductor cable was laid in a trench between the rails. At 9 feet (2.7 m) intervals a box was fitted between the rails that contained a stud (which protruded about 1 inches (25.4 mm) above the road) and a bell crankBell crank
A bell crank is a type of crank that changes motion through an angle. The angle can be any angle from 0 to 360 degrees, although 90 degrees and 180 degrees are common....
. A magnet on a passing tram attracted this crank which then moved to make contact between the conductor cable and stud; once the tram moved away the crank dropped away and the stud was no longer connected to the cable. A long skate was suspended beneath each tramcar which was magnetised by electro-magnets and so both operated the cranks and collected the current that both moved the tram car and powered the electro-magnets. A small battery was carried to charge the electro-magnets should the power be interrupted. The negative return current passed through the rails.
The town council of Torquay did not want their seaside resort disfigured by the poles and overhead wires of a conventional electric tramway and so invited the Dolter Electric Traction Company to construct a tramway using their stud-contact system. A horse was killed after it stepped on a live stud during construction of the Torquay Tramways
Torquay Tramways
Torquay Tramways operated electric street trams in Torquay, Devon, England, from 1907. They were initially powered by the unusual Dolter stud-contact electrification, but in 1911 was converted to more conventional overhead-line supply...
. Each tram car was then fitted with a bell connected to a special contact arm to warn the driver if a stud remained live after it had passed. The conductor of the tram then had to reset the crank using an insulated mallet. During the Board of Trade
Board of Trade
The Board of Trade is a committee of the Privy Council of the United Kingdom, originating as a committee of inquiry in the 17th century and evolving gradually into a government department with a diverse range of functions...
inspection of the tramway four such studs were detected during about 8 miles (12.9 km) of tests. There were also frequent problems with trams being stopped when a stud failed to be made live when needed. The network covered 6.79 miles (10.9 km) and opened in stages during 1907 and 1908. On 27 January 1910 a snow storm stopped all the trams as they couldn't make contact with the studs. It was converted to overhead collection in 1911 shortly before it was extended to Paignton
Paignton
Paignton is a coastal town in Devon in England. Together with Torquay and Brixham it forms the unitary authority of Torbay which was created in 1998. The Torbay area is a holiday destination known as the English Riviera. Paignton's population in the United Kingdom Census of 2001 was 48,251. It has...
where the town council had refused to allow the Dolter system to be used.
A short Dolter system also opened in 1907 in Hastings
Hastings
Hastings is a town and borough in the county of East Sussex on the south coast of England. The town is located east of the county town of Lewes and south east of London, and has an estimated population of 86,900....
along the seafront to connect two sections of a network that otherwise used overhead collection. It lasted until 1913. For the next eight years the trams that worked along Hastings sea front were fitted with a small motor to enable them to move between the two sections of overhead wire, but in 1921 wires were provided along the section.
The Mexborough & Swinton Tramway
Mexborough & Swinton Tramway
The Mexborough & Swinton Tramways Company was a tramway system in South Yorkshire, England, founded in 1902 and which began services in 1907 linking Rotherham with the Old Toll Bar, Denaby...
used the Dolter system from 1907 until 1908 when it was converted to overhead supply.
United Kingdom
- HastingsHastingsHastings is a town and borough in the county of East Sussex on the south coast of England. The town is located east of the county town of Lewes and south east of London, and has an estimated population of 86,900....
(Dolter) - Mexborough & Swinton TramwayMexborough & Swinton TramwayThe Mexborough & Swinton Tramways Company was a tramway system in South Yorkshire, England, founded in 1902 and which began services in 1907 linking Rotherham with the Old Toll Bar, Denaby...
(Dolter) - Torquay TramwaysTorquay TramwaysTorquay Tramways operated electric street trams in Torquay, Devon, England, from 1907. They were initially powered by the unusual Dolter stud-contact electrification, but in 1911 was converted to more conventional overhead-line supply...
(Dolter) - WolverhamptonWolverhamptonWolverhampton is a city and metropolitan borough in the West Midlands, England. For Eurostat purposes Walsall and Wolverhampton is a NUTS 3 region and is one of five boroughs or unitary districts that comprise the "West Midlands" NUTS 2 region...
Corporation Transport (Lorain)
France
- LorientLorientLorient, or L'Orient, is a commune and a seaport in the Morbihan department in Brittany in north-western France.-History:At the beginning of the 17th century, merchants who were trading with India had established warehouses in Port-Louis...
, BrittanyBrittanyBrittany is a cultural and administrative region in the north-west of France. Previously a kingdom and then a duchy, Brittany was united to the Kingdom of France in 1532 as a province. Brittany has also been referred to as Less, Lesser or Little Britain...
, (Diatto) - ParisParisParis is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
, (Diatto) - ToursToursTours is a city in central France, the capital of the Indre-et-Loire department.It is located on the lower reaches of the river Loire, between Orléans and the Atlantic coast. Touraine, the region around Tours, is known for its wines, the alleged perfection of its local spoken French, and for the...
, (Diatto) - Bordeaux (Alimentation par Sol)
See also
- Conduit current collectionConduit current collectionConduit current collection is a system of electric current collection used by electric trams, where the power supply is carried in a channel under the roadway, rather than located overhead.-Description:...
- Ground-level power supplyGround-level power supplyGround-level power supply, also known as surface current collection and Alimentation par Sol is a modern method of third-rail electrical pick-up for street trams. It was invented for the Bordeaux tramway, which was constructed from 2000 and opened in 2003. Until 2011, this is the only place it is...
- Contact shoe
- PantographPantographA pantograph is a mechanical linkage connected in a special manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen...
s - Stud contact electrification on model railwaysStud contact electrification on model railwaysStud contact is a system of electrification for model railways. It was popular in the days before the widespread use of plastics since it permits the use of metal sleepers or track bases, and does not require an insulated section to be inserted in each wheel set.The system is a modification of the...
- Third railThird railA third rail is a method of providing electric power to a railway train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost...