Three-phase electric power
Three-phase electric power is a common method of alternating current electric power generation and distribution. It is a type of polyphase system and is the most common method used by electrical grids worldwide to transfer power, it is used to power large motors and other heavy loads. A three-wire three-phase circuit is more economical than an equivalent two-wire single-phase circuit at the same line to ground voltage because it uses less conductor material to transmit a given amount of electrical power. Polyphase power systems were independently invented by Galileo Ferraris, Mikhail Dolivo-Dobrovolsky, Jonas Wenström, John Hopkinson and Nikola Tesla in the late 1880s; the conductors between a voltage source and a load are called lines, the voltage between any two lines is called line voltage. The voltage measured across any one component is called phase voltage. In a symmetric three-phase power supply system, three conductors each carry an alternating current of the same frequency and voltage amplitude relative to a common reference but with a phase difference of one third of a cycle between each.
The common reference is connected to ground and to a current-carrying conductor called the neutral. Due to the phase difference, the voltage on any conductor reaches its peak at one third of a cycle after one of the other conductors and one third of a cycle before the remaining conductor; this phase delay gives constant power transfer to a balanced linear load. It makes it possible to produce a rotating magnetic field in an electric motor and generate other phase arrangements using transformers; the amplitude of the voltage difference between two phases is 3 times the amplitude of the voltage of the individual phases. The symmetric three-phase systems described here are referred to as three-phase systems because, although it is possible to design and implement asymmetric three-phase power systems, they are not used in practice because they lack the most important advantages of symmetric systems. In a three-phase system feeding a balanced and linear load, the sum of the instantaneous currents of the three conductors is zero.
In other words, the current in each conductor is equal in magnitude to the sum of the currents in the other two, but with the opposite sign. The return path for the current in any phase conductor is the other two phase conductors; as compared to a single-phase AC power supply that uses two conductors, a three-phase supply with no neutral and the same phase-to-ground voltage and current capacity per phase can transmit three times as much power using just 1.5 times as many wires. Thus, the ratio of capacity to conductor material is doubled; the ratio of capacity to conductor material increases to 3:1 with an ungrounded three-phase and center-grounded single-phase system. Constant power transfer and cancelling phase currents would in theory be possible with any number of phases, maintaining the capacity-to-conductor material ratio, twice that of single-phase power. However, two-phase power results in a less smooth torque in a generator or motor, more than three phases complicates infrastructure unnecessarily.
Three-phase systems may have a fourth wire in low-voltage distribution. This is the neutral wire; the neutral allows three separate single-phase supplies to be provided at a constant voltage and is used for supplying groups of domestic properties which are each single-phase loads. The connections are arranged so that, as far as possible in each group, equal power is drawn from each phase. Further up the distribution system, the currents are well balanced. Transformers may be wired in a way that they have a four-wire secondary but a three-wire primary while allowing unbalanced loads and the associated secondary-side neutral currents. Three-phase supplies have properties that make them desirable in electric power distribution systems: The phase currents tend to cancel out one another, summing to zero in the case of a linear balanced load; this makes it possible to reduce the size of the neutral conductor because it carries little or no current. With a balanced load, all the phase conductors so can be the same size.
Power transfer into a linear balanced load is constant, which helps to reduce generator and motor vibrations. Three-phase systems can produce a rotating magnetic field with a specified direction and constant magnitude, which simplifies the design of electric motors, as no starting circuit is required. Most household loads are single-phase. In North American residences, three-phase power might feed a multiple-unit apartment block, but the household loads are connected only as single phase. In lower-density areas, only a single phase might be used for distribution; some high-power domestic appliances such as electric stoves and clothes dryers are powered by a split phase system at 240 volts or from two phases of a three phase system at 208 volts. Wiring for the three phases is identified by color codes which vary by country. Connection of the phases in the right order is required to ensure the intended direction of rotation of three-phase motors. For example and fans may not work in reverse. Maintaining the identity of phases is required if there is any possibility two sources can be connected at the same time.
At the power station, an electrical generator converts mechanical pow
Toronto subway rolling stock
The rolling stock of the Toronto subway system consists of 880 subway cars for Line 1 Yonge–University, Line 2 Bloor–Danforth, Line 4 Sheppard and 28 intermediate-capacity rapid transit cars for Line 3 Scarborough. The rolling stock is maintained by the Toronto Transit Commission. All TTC subway cars are equipped with flip-up seats located in each car, which can accommodate mobility devices such as wheelchairs, strollers and bicycles, the new Toronto Rocket trains have two designated areas in each car with automatic flip-up seats, although level boarding platforms allow a degree of access to all trains; the "Toronto Rocket" "" is the newest version of TTC subway trains, operated on Lines 1 and 4. Its design deviates from its predecessors, which were formed by building trains from married pairs of identical cars; the trains consist of six cars for Line 1 and four cars for Line 4, both of which are connected with open gangways, similar to Bombardier's Movia family of metro trains. They only have two full-width operator cabs per trainset, greater accessibility options and the skin of the train is welded rather than the used riveting method.
The TRs' exterior destination and train run number signs are outfitted with digital orange LED boards, while all previous TTC train models use back-lit roller signs. The first of the new TR trains was scheduled to be delivered in late 2009, but in early 2010, TTC officials stated that the new trains would not enter service until late 2010; the first train arrived on TTC property in October 2010, entered revenue service on July 21, 2011. Most subway work cars are painted yellow with the fleet number as RTXX; the exception are converted subway cars, which are not repainted and have the RT fleet number replacing their former fleet number. Note that RT35 and RT36 are mixed-matched; the TTC uses two different track gauges: 1,435 mm – Line 3 Scarborough, which uses standard gauge 4 ft 10 7⁄8 in – Subway
Automatic train operation
Automatic train operation is an operational safety enhancement device used to help automate operations of trains. It is used on automated guideway transits and rapid transit systems which are easier to ensure safety of humans. Most systems elect to maintain a driver to mitigate risks associated with emergencies. Many modern systems are linked with Automatic Train Control and in many cases Automatic Train Protection where normal signaller operations such as route setting and train regulation are carried out by the system; the ATO and ATC/ATP systems will work together to maintain a train within a defined tolerance of its timetable. The combined system will marginally adjust operating parameters such as the ratio of power to coast when moving and station dwell time, in order to bring a train back to the timetable slot defined for it. According to the International Association of Public Transport, there are five Grades of Automation of trains: GoA 0 is on-sight train operation, similar to a tram running in street traffic.
GoA 1 is manual train operation where a train driver controls starting and stopping, operation of doors and handling of emergencies or sudden diversions. GoA 2 is semi-automatic train operation where starting and stopping is automated, but a driver operates the doors, drives the train if needed and handles emergencies. Many ATO systems are GoA 2. GoA 3 is driverless train operation where starting and stopping are automated but a train attendant operates the doors and drives the train in case of emergencies. GoA 4 is unattended train operation where starting and stopping, operation of doors and handling of emergencies are automated without any on-train staff. On the London Underground, the Victoria, Central and Jubilee lines run with ATO; the Victoria line, opened in 1968, was the world's first full scale automatic railway and the first to have an ATO system replaced. The Circle, Hammersmith & City and Metropolitan lines are being modernised with a brand new automatic train control system; the Glasgow Subway has been using ATO since 1980.
The PATCO Speedline between Philadelphia and Lindenwold, New Jersey, opened its first segment in 1969 as the first ATO line in the United States. On the MTR Network in Hong Kong, all lines operated by MTR Corporation have run with ATO since 1979; the former KCR East Rail Line network has used ATO since 2002. Bay Area Rapid Transit, opened in 1972, was the first new metro system with multiple lines built with ATO; the Vancouver SkyTrain in Vancouver, British Columbia, is an automated and driverless system commissioned in 1985. On the Mass Rapid Transit, all lines operating run with ATO since 1987. All of the lines on the Docklands Light Railway in London have been using ATO since it opened in 1987. On the Nuremberg U-Bahn, existing U2 and new U3 lines converted with one-year mix service. On the Barcelona Metro, the L9, L10 and L11 run with ATO; the Tren Urbano, which serves the San Juan metropolitan area, has a Siemens ATC system that allows for automatic operation. On the Milan Metro, the M1 Red Line runs with ATO.
São Paulo Metrô, Line 4, opened 2010, is the first system operating GoA 4 in South America. On the New York City Subway, the BMT Canarsie Line began full ATO in June 2012. IRT Flushing Line are undergoing track and signal modernization, with completion in 2018. On the Thameslink railway in the core section between St. Pancras and Blackfriars The trains on Dubai metro don't have a driver, neither do the trains on AnsaldoBreda Driverless Metro and some trains of the Rome Metro Aerotrain in Kuala Lumpur, Malaysia is an automatic train. On the Los Angeles Metro system, the Red Line, Purple Line, Green Line use the GoA 2 ATO system. Indonesia's capital city, has a operating public transport that uses the ATO with GoA 2 Level; the Rio Tinto Group "AutoHaul" system on its iron ore railways in the Pilbara which has begun trial operations and is scheduled for completion by the end of 2018. In October 2017 the first autonomous test took place over a 100 kilometres section; the group was granted accreditation by Australia’s Office of the National Rail Safety Regulator, approving the autonomous operation of iron ore trains in the Pilbara region of Western Australia.
Many railways are planning on using ATO. ATO was introduced on the London Underground's Northern line in 2013 and will be introduced on the Circle, Hammersmith & City, Metropolitan lines by 2022. Although ATO will be used on Crossrail and Thameslink, it has not yet been implemented on UK mainline railways; the U-Bahn in Vienna gets an ATO in 2023 on the new U5 line. All lines being built for the new Sydney Metro will feature driverless operation without any attended staff present; the Toronto Subway and RT is undergoing signal upgrades in order to switch to have the system running on ATO over the next decade. ATO is in everyday operation on Czech Railways lines since 1991, since 2008 in test operation with ETCS; the Delhi Metro officials have stated that driverless trains with advanced features will run on the Botanical Garden - Kalkaji corridor with trial runs planned for the last week of July 2016 and the trains being operated on the route from August 2016 onwards. Drivers will be deputed to operate the trains but they will be withdrawn said a metro official.
List of automated urban metro subway systems Automation of the London Underground Communications-based train control – A
Electric current collectors are used by trolleybuses, electric locomotives or EMUs to carry electrical power from overhead lines or electrical third rails to the electrical equipment of the vehicles. Those for overhead wires are roof-mounted devices, those for third rails are mounted on the bogies, they have one or more spring-loaded arms that press a collector or contact shoe against the rail or overhead wire. As the vehicle moves, the contact shoe slides along the wire or rail to draw the electricity needed to run the vehicle's motor; the current collector arms are electrically conductive but mounted insulated on the vehicle's roof, side or base. An insulated cable connects the collector with the transformer or motor; the steel rails of the tracks act as the electrical return. Electric vehicles that collect their current from an overhead line system use different forms of one- or two-arm pantograph collectors, bow collectors or trolley poles; the current collection device presses against the underside of the lowest wire of an overhead line system, called a contact wire.
Most overhead supply systems are either DC or single phase AC, using a single wire with return through the grounded running rails. Three phase AC systems use a pair of overhead wires, paired trolley poles. Electric railways with third rails, or fourth rails, in tunnels carry collector shoes projecting laterally, or vertically, from their bogies; the contact shoe may slide on the bottom or on the side. The side running contact shoe is used against the guide bars on rubber-tired metros. A vertical contact shoe is used on ground-level power supply systems, stud contact systems and fourth rail systems. A pair of contact shoes was used on underground current collection systems; the contact shoe on a stud contact system is called a ski collector. The ski collector moves vertically to accommodate slight variations in the height of the studs. Contact shoes may be used on overhead conductor rails, on guide bars or on trolley wires. Most railways use three rails. TRUCK
A livery is a uniform, insignia or symbol adorning, in a non-military context, a person, an object or a vehicle that denotes a relationship between the wearer of the livery and an individual or corporate body. Elements of the heraldry relating to the individual or corporate body feature in the livery. Alternatively, some kind of a personal emblem or badge, or a distinctive colour, is featured; the word meaning dispensed, handed over. Most it would indicate that the wearer of the livery was a servant, follower or friend of the owner of the livery, or, in the case of objects, that the object belonged to them. In the late medieval phenomenon of bastard feudalism, livery badges worn by the "retainers" of great lords, sometimes in effect private armies, became a great political concern in England. In the 14th century, "livery" referred to an allowance of any kind, but clothes provided to servants and members of the household; such things might be kept in a "livery cupboard". During the 12th century, specific colours denoting a great person began to be used for both his soldiers and his civilian followers, the modern sense of the term began to form.
Two different colours were used together, but the ways in which they were combined varied with rank. The colours used were different each year; as well as embroidered badges, metal ones were sewn on to clothing, or hung on neck-chains or livery collars. From the 16th century onwards, only the lower-status followers tended to receive clothes in livery colours and the term "servant" much wider began to be restricted to describing the same people. Municipalities and corporations copied the behaviour of the great households; the term is used to describe badges and grander pieces of jewellery containing the heraldic signs of an individual, which were given by that person to friends and distinguished visitors, as well as servants. The grandest of these is the livery collar. William, Lord Hastings the favourite of King Edward IV of England had a "Coller of gold of K. Edward's lyverys" valued at the enormous sum of £40 in an inventory of 1489; this would have been similar to the collars worn by Hastings' sister and her husband Sir John Donne in the Donne Triptych by Hans Memling.
Lords gave their servants pewter badges to sew onto their clothes. In the 15th century European royalty sometimes distributed uniform suits of clothes to courtiers, as the House of Fugger, the leading bankers, did to all employees; this practice contracted to the provision of standardized clothing to male servants in a colour-scheme distinctive to a particular family. The term most notably referred to the embroidered coats, knee breeches and stockings in 18th-century style, worn by footmen on formal occasions in grand houses. Plainer clothing in dark colours and without braiding was worn by footmen and other employees for ordinary duties. For reasons of economy the employment of such servants, their expensive dress, died out after World War I except in royal households. Most European royal courts still use their state liveries on formal occasions; these are in traditional national colours, are based on 18th century clothing with fine gold embroidery. Only male royal servants wear livery. Knee breeches are worn with white silk stockings.
At the British royal court red state livery is still worn by pages, footmen and other attendants on state and formal occasions. The state livery worn by footmen includes foils; the scarlet coats are handmade, embroidered in gold braid with the royal cypher of the monarch. Gold buttons and other trimmings are of patterns which date from the 18th century. Unlike the tailor-made uniform clothing issued to full-time royal staff, the seldom-worn full-state dress reserved for court pages is not bespoke; the usual practice is to select pages whose height fits the existing ceremonial coats held in storage. At the Belgian court liveries in traditional colours are still used at state occasions; the coats are red, have black cuffs with golden lace. Royal cyphers are embroidered on the shoulders; the breeches are of yellow fabric. The semi-state livery worn for less formal occasions has black breeches. At the Dutch court the full state livery is blue; the breeches are yellow, cuffs are red. The phrase "to sue one's livery" refers to the formal recognition of a noble's majority, in exchange of payment, for conferring the powers attached to his title, thereby freeing him from dependence as a ward.
From this core meaning, multiple extended or specialist meanings have derived. Examples include: A livery company is the name used for a guild in the City of London. Following on from the decoration of the nobility's horse-drawn carriages in their owner's livery colours, a livery is the common design and paint scheme a business will use on its vehicles using specific colors and logo placement. In this sense, the term is applied to railway locomotives and rolling stock, ships and road vehicles. For example, United Parcel Service has trucks with a well-known brown livery. Another example is the British Airways ethnic liveries; the term has become extended to the logos and other disti
The Flexity Freedom is a low-floor, articulated light rail vehicle developed by Bombardier Transportation for the North American market. It is marketed as part of its Flexity family which includes other models of trams and light metro vehicles, they are produced in facilities in Thunder Bay and Kingston, which once produced rolling stock under the names of Canada Car and Foundry and Urban Transportation Development Corporation, respectively. The Flexity Freedom is to be used on the Ion rapid transit in Waterloo, Line 5 Eglinton in Toronto, the Valley Line in Edmonton. Being low-floor, these vehicles directly compete with the Flexity Swift, Alstom Citadis, Siemens S70, CAF Urbos, Kinki Sharyo LRVs. However, as they are designed for light rail rather than streetcar applications, they compete against, to a lesser extent, low-floor streetcars from Skoda/Inekon and Brookville Equipment Corporation, among others; the vehicles all have a 100% low-floor design and can be built to operate unidirectionally or bidirectionally.
The vehicles' design includes energy-saving features, like regenerative braking and the use of LED lighting, but they are air-conditioned. The vehicles may be coated in special paint designed to resist graffiti, they are equipped with passenger counters at the doors. The vehicles are articulated, but unlike competing rolling stock, they are built out of similar-length modules. Operators can alter the number of intermediate modules, thus altering the capacity of the individual vehicles; the Toronto and Kitchener-Waterloo vehicles will contain five modules, while those in Edmonton will have seven modules. Vehicles can be operated as trains of up to four connected vehicles; the maximum passenger capacities, in the standard seating layouts, are 135 and 251, for the three and five-module configurations respectively. When run in the five-module configuration, with train-sets of four vehicles, the maximum capacity of a light rail line is 30,000 passengers per peak hour; the vehicles' standard passenger configuration can safely accommodate up to four passengers in wheelchairs.
For example, the trains for Edmonton will carry up to 275 passengers per trains. According to Bombardier, the trainsets can be built for "catenary-free" power, instead of being powered by direct contact with overhead wires they are powered indirectly through induction, through buried loops, a form of ground-level power supply competing directly with Alstom's "APS" system. Flexity Freedom vehicles are technically similar to the Flexity Outlook vehicles in production for the Toronto streetcar system, but are wider and capable of higher speeds, use standard gauge rather than the streetcar system's broad gauge. All current production models have cabs on both ends and doors on both sides, while the Flexity Outlook have only one cab and doors on one side, as with all previous generations of streetcars. While Flexity Outlook vehicles are able to negotiate the tight curves of the on-street trackage and its single-point switches, Flexity Freedom vehicles require a minimum curve radius of 25 metres and conventional double-point switches.
The light rail lines in Toronto will be constructed to standard gauge instead of Toronto's streetcar gauge because Metrolinx, the Ontario provincial transit authority funding the projects, wants to ensure a better price for purchasing vehicles by having a degree of commonality with other similar projects within Ontario. The Flexity Freedom cars were designed for the Transit City plan which would have created six suburban LRT lines for an order of about 300 cars. Only two of these projects were active in 2016: the Eglinton Crosstown line, the first to go into construction, the Finch West LRT, approved later. Metrolinx placed its first order for 182 vehicles under a $770 million contract announced in 2010. Of the 182 vehicles ordered, 76 are for the Eglinton Crosstown line and 23 for the Finch West LRT. Bombardier expects deliveries to start in 2018. By May 2016, Metrolinx had not received the prototype vehicle that Bombardier was supposed to produce by spring 2015; the prototype, once received, will be tested for one or two years to work out any design bugs before Bombardier begins to manufacture the rest of the order.
In July 2016, Bombardier spokesman Marc-André Lefebvre acknowledged receipt of "a contractual notice" from Metrolinx complaining about the delay in delivery of the prototype vehicle. Lefebvre said that the prototype will be delivered in August giving Metrolinx 18 months to test the vehicle, about double the time needed for testing. Lefebvre said production will begin in spring 2018 and the remainder of the 182-car order will be delivered in time for the scheduled opening of the line. On September 1, 2016, Bombardier said the prototype was nearing completion at the Thunder Bay plant and would be available for testing in 3–4 weeks. In September 2016, the province allowed consortia to include the delivery of light-rail vehicles in their bid to build the Finch LRT; this implies. In November 2016, Metrolinx gave formal notice of intent to cancel its $770-million contract with Bombardier. Metrolinx alleged unacceptable delivery delays fearing that the opening of the Eglinton Crosstown line would be delayed due to a lack of vehicles.
Bombardier claimed. Metrolinx alleged that the prototype could not handle basic functions such as taking power from an overhead catenary. Bombardier claimed the prototype functioned properly, that it was conducting static tests before doing moving tests with power taken from a catenary. In late November 2016, Bombardier shipped