1.
Light rail
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Light rail, light rail transit or fast tram is urban public transport using rolling stock similar to a tramway, but operating at a higher capacity, and often on an exclusive right-of-way. A few light rail networks tend to have closer to rapid transit or even commuter rail. Other light rail networks are tram-like in nature and partially operate on streets, Light rail systems are found throughout the world, on all inhabited continents. They have been popular in recent years due to their lower capital costs. The term light rail was coined in 1972 by the U. S, Urban Mass Transportation Administration to describe new streetcar transformations that were taking place in Europe and the United States. In Germany the term Stadtbahn was used to describe the concept, and many in UMTA wanted to adopt the direct translation, however, UMTA finally adopted the term light rail instead. Light in this context is used in the sense of intended for light loads and fast movement, the infrastructure investment is also usually lighter than would be found for a heavy rail system. The Transportation Research Board defined light rail in 1977 as a mode of urban transportation utilizing predominantly reserved, electrically propelled rail vehicles operate singly or in trains. LRT provides a range of passenger capabilities and performance characteristics at moderate costs. Light rail is a generic international English phrase for these types of rail systems, the use of the generic term light rail avoids some serious incompatibilities between British and American English. The word trolley is used as a synonym for streetcar in the United States. A further difference arose because, while Britain abandoned all of its trams except Blackpool after World War II, when these cities upgraded to new technology, they called it light rail to differentiate it from their existing streetcars since some continued to operate both the old and new systems. Conventional rail technologies including high-speed, freight, commuter/regional, and metro/subway/elevated urban transit systems are considered heavy rail, people movers and personal rapid transit are even lighter, at least in terms of capacity. Monorail is a technology that has been more successful in specialized services than in a commuter transit role. Due to varying definitions, it is hard to distinguish between what is called light rail, and other forms of urban and commuter rail, a system described as light rail in one city may be considered to be a streetcar or tram system in another. Conversely, some lines that are called light rail are in very similar to rapid transit, in recent years. Some light rail systems, such as Sprinter, bear little similarity to urban rail, in the United States, light rail has become a catch-all term to describe a wide variety of passenger rail systems. There is a significant difference in cost between these different classes of light rail transit, tram-like systems are often less expensive than metro-like systems by a factor of two or more
2.
Regional Transportation District
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It operates over a 2, 340-square-mile area, serving 2.87 million people. RTD is governed by a 15-member, publicly elected Board of Directors, Directors are elected to a four-year term and represent a specific district of about 180,000 constituents. RTD currently operates a bus and rail system that has an area of 2,337 square miles. It employed 2,734 people and reported 103 million boardings in 2016 and it had a $466.7 million operating budget for the year of 2015. Google has RTD schedules attached to its trip planner, and 3rd party mobile applications are now available for the iPhone,1969, RTD was created in the 47th session of the Colorado General Assembly to provide public transportation to five additional counties in the metropolitan area. 1969–1971, The Denver Tramway Company continues service under sponsorship of the City and County of Denver, October 1970, RTD found it needed to establish a Northern Operations Group to provide service to Boulder and Longmont. RTD also acquired the privately owned Denver-Boulder Bus Company, which ran airport buses,1971, Denver Metro Transit took over the privately owned Denver Tramway Company. Denver Metro Transit was an entity created by the City and County of Denver, suburban service only continued for those suburbs willing to contribute a subsidy. 1972, RTD created a plan for a rapid transit system in the area. This plan included 98 miles of PRT and extensive bus service throughout the areas served by RTD, later that year, the Urban Mass Transportation Administration selected RTD to develop PRT as a demonstration project. The PRT project was eventually scrapped, the tax became effective January 1,1974. July 1974, Denver Metro Transit became part of RTD, 1975–1977, RTD consolidated, expanded, and improved service frequency. Service was expanded to routes that commercial carriers previously operated, february 1978, Inflation caused RTD to implement a new fare structure. For instances, the new Colorado Blvd route was number 40,1979, Federal approval was granted for the 16th Street Mall in downtown Denver, originally known as Transitway. The project allowed express bus productivity to double and was intersected by RTDs first light rail line. 1980, RTD reached a number of weekday passengers. It also acquired 216 new buses,89 of which were articulated, construction began on the 16th Street Mall. Work was also completed to make RTDs service more accessible to elderly,1983, On May 1,1983, the tax was increased to 0. 6%
3.
Denver metropolitan area
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Denver is the central city of a conurbation region in the U. S. state of Colorado. The conurbation includes one continuous region consisting of the six counties of Adams, Arapahoe, Broomfield, Denver, Douglas. The Denver region is part of the Front Range Urban Corridor, the continuously urbanized area extends northwest into the City and County of Broomfield, bordering Jefferson and Adams counties, and south into Douglas County, adjoining Arapahoe County. Also included in the federally defined MSA are four counties, Elbert County on the southeastern prairie and Clear Creek, Gilpin. The Denver-Aurora-Lakewood Metropolitan Statistical Area comprises ten counties, in 2005 the RTD developed a twelve-year comprehensive plan, called FasTracks, to build and operate rail transit lines and expand and improve bus service throughout the region. Electricity is provided by Xcel Energy, cable television is provided by Comcast. Severity of pollution in this area has varied enormously over the years, in the late 1980s the area was frequently in violation of multiple National Ambient Air Quality Standards established by the United States Environmental Protection Agency. The Regional Air Quality Council was formed in 1989 to create plans to address the problem, through a variety of measures the areas air quality was improved and in 2002 the EPA designated the area in compliance with all federal health-based air quality standards. Denver was the first major city in the United States to reach compliance with all six of these standards after previously violating five of them, since then the EPA introduced a new standard for small particulates and made the existing ozone standard stricter. In 2003 the new standard was frequently exceeded in the area and was occasionally exceeded as far away as Rocky Mountain National Park. The RAQC hopes to implement plans enabling the area to comply with the new standards by 2007. S
4.
Peoria station
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Peoria, also known as Peoria/Smith, is a Regional Transportation District station in Aurora, Colorado. A Line travel times from the station to Downtown Denver and Denver International Airport are about 17 and 20 minutes, Peoria station is the northern terminus of the R Line with a travel time of 58 minutes to the southern terminus at Lincoln station. Peoria and Union Station are the two locations where RTD commuter rail and light meet, and Peoria is the only station facilitating a cross-platform transfer between the two systems. Peoria station is served by several TheRide bus routes and has a 550-space park-and-ride lot. The A Line began service at Peoria station on April 22,2016, the R Line began service on February 24,2017
5.
Track gauge
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In rail transport, track gauge is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails. All vehicles on a network must have running gear that is compatible with the track gauge, as the dominant parameter determining interoperability, it is still frequently used as a descriptor of a route or network. There is a distinction between the gauge and actual gauge at some locality, due to divergence of track components from the nominal. Railway engineers use a device, like a caliper, to measure the actual gauge, the nominal track gauge is the distance between the inner faces of the rails. In current practice, it is specified at a distance below the rail head as the inner faces of the rail head are not necessarily vertical. In some cases in the earliest days of railways, the company saw itself as an infrastructure provider only. Colloquially the wagons might be referred to as four-foot gauge wagons, say and this nominal value does not equate to the flange spacing, as some freedom is allowed for. An infrastructure manager might specify new or replacement track components at a variation from the nominal gauge for pragmatic reasons. Track is defined in old Imperial units or in universally accepted metric units or SI units, Imperial units were established in United Kingdom by The Weights and Measures Act of 1824. In addition, there are constraints, such as the load-carrying capacity of axles. Narrow gauge railways usually cost less to build because they are lighter in construction, using smaller cars and locomotives, as well as smaller bridges, smaller tunnels. Narrow gauge is often used in mountainous terrain, where the savings in civil engineering work can be substantial. Broader gauge railways are generally expensive to build and require wider curves. There is no single perfect gauge, because different environments and economic considerations come into play, a narrow gauge is superior if ones main considerations are economy and tight curvature. For direct, unimpeded routes with high traffic, a broad gauge may be preferable, the Standard, Russian, and 46 gauges are designed to strike a reasonable balance between these factors. In addition to the general trade-off, another important factor is standardization, once a standard has been chosen, and equipment, infrastructure, and training calibrated to that standard, conversion becomes difficult and expensive. This also makes it easier to adopt an existing standard than to invent a new one and this is true of many technologies, including railroad gauges. The reduced cost, greater efficiency, and greater economic opportunity offered by the use of a common standard explains why a number of gauges predominate worldwide
6.
Railway electrification system
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A railway electrification system supplies electric power to railway trains and trams without an on-board prime mover or local fuel supply. Electrification has many advantages but requires significant capital expenditure, selection of an electrification system is based on economics of energy supply, maintenance, and capital cost compared to the revenue obtained for freight and passenger traffic. Different systems are used for urban and intercity areas, some electric locomotives can switch to different supply voltages to allow flexibility in operation, Electric railways use electric locomotives to haul passengers or freight in separate cars or electric multiple units, passenger cars with their own motors. Electricity is typically generated in large and relatively efficient generating stations, transmitted to the railway network, some electric railways have their own dedicated generating stations and transmission lines but most purchase power from an electric utility. The railway usually provides its own lines, switches and transformers. Power is supplied to moving trains with a continuous conductor running along the track usually takes one of two forms. The first is a line or catenary wire suspended from poles or towers along the track or from structure or tunnel ceilings. Locomotives or multiple units pick up power from the wire with pantographs on their roofs that press a conductive strip against it with a spring or air pressure. Examples are described later in this article, the second is a third rail mounted at track level and contacted by a sliding pickup shoe. Both overhead wire and third-rail systems usually use the rails as the return conductor. In comparison to the alternative, the diesel engine, electric railways offer substantially better energy efficiency, lower emissions. Electric locomotives are usually quieter, more powerful, and more responsive and they have no local emissions, an important advantage in tunnels and urban areas. Different regions may use different supply voltages and frequencies, complicating through service, the limited clearances available under catenaries may preclude efficient double-stack container service. Possible lethal electric current due to risk of contact with high-voltage contact wires, overhead wires are safer than third rails, but they are often considered unsightly. These are independent of the system used, so that. The permissible range of voltages allowed for the voltages is as stated in standards BS EN50163. These take into account the number of trains drawing current and their distance from the substation, railways must operate at variable speeds. Until the mid 1980s this was only practical with the brush-type DC motor, since such conversion was not well developed in the late 19th century and early 20th century, most early electrified railways used DC and many still do, particularly rapid transit and trams
7.
Overhead line
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An overhead line or overhead wire is used to transmit electrical energy to trams, trolleybuses, or trains. Overhead line is designed on the principle of one or more overhead wires situated over rail tracks, the feeder stations are usually fed from a high-voltage electrical grid. Electric trains that collect their current from overhead lines use a device such as a pantograph and it presses against the underside of the lowest overhead wire, the contact wire. Current collectors are electrically conductive and allow current to flow through to the train or tram, non-electric locomotives may pass along these tracks without affecting the overhead line, although there may be difficulties with overhead clearance. Alternative electrical power transmission schemes for trains include third rail, ground-level power supply, batteries and this article does not cover regenerative braking, where the traction motors act as generators to retard movement and return power to the overhead. To achieve good high-speed current collection, it is necessary to keep the wire geometry within defined limits. This is usually achieved by supporting the wire from a second wire known as the messenger wire or catenary. This wire approximates the path of a wire strung between two points, a catenary curve, thus the use of catenary to describe this wire or sometimes the whole system. This wire is attached to the wire at regular intervals by vertical wires known as droppers or drop wires. It is supported regularly at structures, by a pulley, link, the whole system is then subjected to a mechanical tension. As the contact wire makes contact with the pantograph, the insert on top of the pantograph is worn down. The straight wire between supports will cause the wire to cross over the whole surface of the pantograph as the train travels around the curve, causing uniform wear. On straight track, the wire is zigzagged slightly to the left. The movement of the wire across the head of the pantograph is called the sweep. The zigzagging of the line is not required for trolley poles. Depot areas tend to have only a wire and are known as simple equipment or trolley wire. When overhead line systems were first conceived, good current collection was only at low speeds. Compound equipment - uses a second wire, known as the auxiliary
8.
Volt
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The volt is the derived unit for electric potential, electric potential difference, and electromotive force. One volt is defined as the difference in potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. It is also equal to the difference between two parallel, infinite planes spaced 1 meter apart that create an electric field of 1 newton per coulomb. Additionally, it is the difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can also be expressed as amperes times ohms, watts per ampere, or joules per coulomb, for the Josephson constant, KJ = 2e/h, the conventional value KJ-90 is used, K J-90 =0.4835979 GHz μ V. This standard is typically realized using an array of several thousand or tens of thousands of junctions. Empirically, several experiments have shown that the method is independent of device design, material, measurement setup, etc. in the water-flow analogy sometimes used to explain electric circuits by comparing them with water-filled pipes, voltage is likened to difference in water pressure. Current is proportional to the diameter of the pipe or the amount of water flowing at that pressure. A resistor would be a reduced diameter somewhere in the piping, the relationship between voltage and current is defined by Ohms Law. Ohms Law is analogous to the Hagen–Poiseuille equation, as both are linear models relating flux and potential in their respective systems, the voltage produced by each electrochemical cell in a battery is determined by the chemistry of that cell. Cells can be combined in series for multiples of that voltage, mechanical generators can usually be constructed to any voltage in a range of feasibility. High-voltage electric power lines,110 kV and up Lightning, Varies greatly. Volta had determined that the most effective pair of metals to produce electricity was zinc. In 1861, Latimer Clark and Sir Charles Bright coined the name volt for the unit of resistance, by 1873, the British Association for the Advancement of Science had defined the volt, ohm, and farad. In 1881, the International Electrical Congress, now the International Electrotechnical Commission and they made the volt equal to 108 cgs units of voltage, the cgs system at the time being the customary system of units in science. At that time, the volt was defined as the difference across a conductor when a current of one ampere dissipates one watt of power. The international volt was defined in 1893 as 1/1.434 of the emf of a Clark cell and this definition was abandoned in 1908 in favor of a definition based on the international ohm and international ampere until the entire set of reproducible units was abandoned in 1948. Prior to the development of the Josephson junction voltage standard, the volt was maintained in laboratories using specially constructed batteries called standard cells
9.
Direct current
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Direct current is a flow of electrical charge carriers that always takes place in the same direction. The current need not always have the magnitude, but if it is to be defined as dc. This contrasts with alternating current which varies the direction of flow, sources of direct current include power supplies, electrochemical cells and batteries, and photovoltaic cells and panels. The intensity, or amplitude, of a direct current might fluctuate with time, in some such cases the dc has an ac component superimposed on it. An example of this is the output of a cell that receives a modulated light communications signal. A source of dc is sometimes called a dc generator, batteries and various other sources of dc produce a constant voltage. This is called pure dc and can be represented by a straight, the peak and effective values are the same. The peak to peak value is zero because the instantaneous amplitude never changes, in some instances the value of a dc voltage pulsates or oscillates rapidly with time, in a manner similar to the changes in an ac wave. The unfiltered output of a wave or a full wave rectifier. In 1820, Hans Christian Orsted discovered that electrical current creates a magnetic field and this discovery made scientists relate magnetism to the electric phenomena. In 1879, Thomas Edison invented the light bulb. He improved a 50-year-old idea using lower current electricity, a vacuum inside the globe and a small carbonized filament. At that time, the idea of lightning was not new. Edison not only invented an incandescent electric light, but an electric lighting system contained all the necessary elements to make the incandescent light safe, economical. Prior to 1879, direct current electricity had been used in lighting for the outdoors and it was in the 1880s when the modern electric utility industry began. It was an evolution from street lighting systems and from gas and it was located in Lower Manhattan, on Pearl Street. This station provided light and electricity to customers in a one square mile range, the station was called Thomas Edisons Pearl Street Electricity Generating Station. This station introduced four elements of an electric utility system, Efficient distribution, competitive price, reliable central generation
