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110-765: In 2018, Amazon.com, Inc. announced plans to locate part of its " HQ2 " second headquarters project in Northern Virginia, specifically in the newly re-branded cross-jurisdictional neighborhood of National Landing , which local and state officials said would include Potomac Yard as well as nearby parts of southern Arlington, including the Crystal City neighborhood that will be the hub of the HQ2 development. Amazon initially planned to split HQ2 between National Landing and Long Island City, New York , but opposition from New York officials led Amazon to cancel that portion of

220-413: A block and tackle arrangement. Lines are divided into sections to limit the scope of an outage and to allow maintenance. To allow maintenance to the overhead line without having to turn off the entire system, the line is broken into electrically separated portions known as "sections". Sections often correspond with tension lengths. The transition from section to section is known as a "section break" and

330-752: A physical retailer . Amazon also distributes a variety of downloadable and streaming content through its Amazon Prime Video , MGM+ , Amazon Music , Twitch, Audible and Wondery units. It publishes books through its publishing arm, Amazon Publishing , film and television content through Amazon MGM Studios , including the Metro-Goldwyn-Mayer studio, which was acquired in March 2022, and owns Brilliance Audio and Audible, which produce and distribute audiobooks, respectively. Amazon also produces consumer electronics —most notably, Kindle e-readers , Echo devices, Fire tablets , and Fire TVs . Amazon has

440-419: A swing bridge . The catenary wire typically comprises messenger wire (also called catenary wire) and a contact wire where it meets the pantograph. The messenger wire is terminated at the portal, while the contact wire runs into the overhead conductor rail profile at the transition end section before it is terminated at the portal. There is a gap between the overhead conductor rail at the transition end section and

550-476: A "Backdoor" connection between different parts, resulting in, amongst other things, a section of the grid de-energised for maintenance being re-energised from the railway substation creating danger. For these reasons, Neutral sections are placed in the electrification between the sections fed from different points in a national grid, or different phases, or grids that are not synchronized. It is highly undesirable to connect unsynchronized grids. A simple section break

660-492: A 10-year agreement with Amazon, valued at $ 50 million per year plus a cut of sales, under which Toys "R" Us would be the exclusive supplier of toys and baby products on the service, and the chain's website would redirect to Amazon's Toys & Games category. In 2004, Toys "R" Us sued Amazon, claiming that because of a perceived lack of variety in Toys "R" Us stock, Amazon had knowingly allowed third-party sellers to offer items on

770-570: A 25-acre (100,000 m) park, which will be owned by Arlington County. A mixed-use development apartment community called Station 650 was completed in 2015 in the Potomac Yard redevelopment of Alexandria , Virginia . The project by Wood Partners includes 183 residential units in a five-story building with street-level retail. In December 2023 it was announced that the Washington Capitals and Washington Wizards would move to

880-494: A co-branded service. Borders pulled out of the arrangement in 2007, with plans to also launch its own online store. On October 18, 2011, Amazon.com announced a partnership with DC Comics for the exclusive digital rights to many popular comics, including Superman , Batman , Green Lantern , The Sandman , and Watchmen . The partnership has caused well-known bookstores like Barnes & Noble to remove these titles from their shelves. In November 2013, Amazon announced

990-411: A fixed centre point, with the two half-tension lengths expanding and contracting with temperature. Most systems include a brake to stop the wires from unravelling completely if a wire breaks or tension is lost. German systems usually use a single large tensioning pulley (basically a ratchet mechanism) with a toothed rim, mounted on an arm hinged to the mast. Normally the downward pull of the weights and

1100-505: A fixed price. Publishers can sign up as affiliates and receive a commission for referring customers to Amazon by placing links to Amazon on their websites if the referral results in a sale. Worldwide, Amazon has "over 900,000 members" in its affiliate programs. In the middle of 2014, the Amazon Affiliate Program is used by 1.2% of all websites and it is the second most popular advertising network after Google Ads . It

1210-590: A global chat on the livestream. In 2019 Amazon launched an integrated platform into the Amazon website and application . In 2023 roughly a billion total viewers watch Amazon Live across the United States and India. The platform has also been integrated into Amazon Freevee and Amazon Prime Video . Amazon Web Services (AWS) is a subsidiary of Amazon that provides on-demand cloud computing platforms and APIs to individuals, companies, and governments, on

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1320-564: A guide of general interest for the customer and not definitive sales information for publishers—we assume you have this information regularly from your distribution sources In November 2015, Amazon opened a physical Amazon Books store in University Village in Seattle . The store was 5,500 square feet and prices for all products matched those on its website. Amazon opened its tenth physical book store in 2017; media speculation at

1430-485: A high electrical potential by connection to feeder stations at regularly spaced intervals along the track. 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 , bow collector or trolley pole . 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

1540-484: A level crossing with the 1,200 V DC Uetliberg railway line ; at many places, trolleybus lines cross the tramway. In some cities, trolleybuses and trams shared a positive (feed) wire. In such cases, a normal trolleybus frog can be used. Alternatively, section breaks can be sited at the crossing point, so that the crossing is electrically dead. Many cities had trams and trolleybuses using trolley poles. They used insulated crossovers, which required tram drivers to put

1650-466: A metered pay-as-you-go basis. These cloud computing web services provide distributed computing processing capacity and software tools via AWS server farms . As of 2021 Q4, AWS has 33% market share for cloud infrastructure while the next two competitors Microsoft Azure and Google Cloud have 21%, and 10% respectively, according to Synergy Group. Audible is a seller and producer of spoken audio entertainment, information, and educational programming on

1760-579: A multiple unit passes over them. In the United Kingdom equipment similar to Automatic Warning System (AWS) is used, but with pairs of magnets placed outside the running rails (as opposed to the AWS magnets placed midway between the rails). Lineside signs on the approach to the neutral section warn the driver to shut off traction power and coast through the dead section. A neutral section or phase break consists of two insulated breaks back-to-back with

1870-468: A new arena to be built at Potomac Yard. The site would include training facilities, team offices, and a performing arts venue. Construction for Potomac Yard Park began in 2009, and it opened on December 14, 2013. The park contains a water fountain, playgrounds, and sports fields within 24 acres. Located south of the main shopping district, it borders train tracks carrying freight and Virginia Railway Express commuter rail. The City of Alexandria has erected

1980-869: A notification if it detects something unusual. In January 2023, Amazon announced the launch of RXPass, a prescription drug delivery service. It allows U.S. Amazon Prime members to pay a $ 5 monthly fee for access to 60 medications. The service was launched immediately after the announcement except in states with specific prescription delivery requirements. Beneficiaries of government healthcare programs such as Medicare and Medicaid will not be able to sign up for RXPass. Amazon owns over 100 subsidiaries, including Amazon Web Services , Audible , Diapers.com, Goodreads , IMDb , Kiva Systems (now Amazon Robotics ), One Medical , Shopbop , Teachstreet, Twitch , Zappos , and Zoox . Bezos separately owns The Washington Post (through Nash Holdings, LLC), Blue Origin , Bezos Expeditions , Altos Labs , and other companies. Amazon Live

2090-617: A partnership with the United States Postal Service to begin delivering orders on Sundays. The service, included in Amazon's standard shipping rates, initiated in metropolitan areas of Los Angeles and New York because of the high-volume and inability to deliver in a timely way, with plans to expand into Dallas , Houston , New Orleans and Phoenix by 2014. In June 2017, Nike agreed to sell products through Amazon in exchange for better policing of counterfeit goods. This proved unsuccessful and Nike withdrew from

2200-961: A plan was adopted for Jeff Bezos to sell approximately 50 million shares of the company over the next year (the deadline for the entire sales plan is January 31, 2025). The first step was the sale of 12 million shares for about $ 2 billion. On February 26, 2024, Amazon became a component of the Dow Jones Industrial Average . Amazon.com is an e-commerce platform that sells many product lines, including media ( books , movies, music, and software), apparel, baby products, consumer electronics , beauty products , gourmet food, groceries, health and personal care products, industrial & scientific supplies, kitchen items, jewelry , watches, lawn and garden items, musical instruments, sporting goods , tools, automotive items, toys and games, and farm supplies and consulting services . Amazon websites are country-specific (for example, amazon.com for

2310-404: A pneumatic servo pantograph with only 3  g acceleration. An electrical circuit requires at least two conductors. Trams and railways use the overhead line as one side of the circuit and the steel rails as the other side of the circuit. For a trolleybus or a trolleytruck , no rails are available for the return current, as the vehicles use rubber tyres on the road surface. Trolleybuses use

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2420-774: A previously scheduled opening date of April 2022 was pushed back due to a safety issue with the automatic train control systems. A streetcar system in Northern Virginia was proposed to open in 2020, with trains traveling between Potomac Yard, Crystal City, Pentagon City , and Bailey's Crossroads . In late November 2014 the Arlington County Board cancelled the streetcar plan. 38°49′47″N 77°02′59″W  /  38.8296006°N 77.049618°W  / 38.8296006; -77.049618 Amazon (company) Amazon.com, Inc. , doing business as Amazon ( / ˈ æ m ə z ɒ n / , AM -ə-zon ; UK also / ˈ æ m ə z ə n / , AM -ə-zən ),

2530-401: A range of Booths branded products for home delivery in selected areas. In November 2018, Amazon reached an agreement with Apple Inc. to sell selected products through the service, via the company and selected Apple Authorized Resellers. As a result of this partnership, only Apple Authorized Resellers may sell Apple products on Amazon effective January 4, 2019. On November 7, 2024 Amazon

2640-429: A reputation as a disruptor of industries through technological innovation and aggressive reinvestment of profits into capital expenditures. As of 2023 , it is the world's largest online retailer and marketplace , smart speaker provider, cloud computing service through AWS, live-streaming service through Twitch, and Internet company as measured by revenue and market share . In 2021, it surpassed Walmart as

2750-415: A return path for the current through their wheels, and must instead use a pair of overhead wires to provide both the current and its return path. To achieve good high-speed current collection, it is necessary to keep the contact wire geometry within defined limits. This is usually achieved by supporting the contact wire from a second wire known as the messenger wire or catenary . This wire approximates

2860-414: A rigid overhead wire in their tunnels, while using normal overhead wires in their above ground sections. In a movable bridge that uses a rigid overhead rail, there is a need to transition from the catenary wire system into an overhead conductor rail at the bridge portal (the last traction current pylon before the movable bridge). For example, the power supply can be done through a catenary wire system near

2970-468: A second parallel overhead line for the return, and two trolley poles , one contacting each overhead wire. ( Pantographs are generally incompatible with parallel overhead lines.) The circuit is completed by using both wires. Parallel overhead wires are also used on the rare railways with three-phase AC railway electrification . In the Soviet Union the following types of wires/cables were used. For

3080-733: A series of seven signs in Potomac Yard Park that sequentially describe and illustrate the history of the area. These include: Point 1: Virginia's First Highways Point 2: The Alexanders & Agriculture Point 3: Building Potomac Yard Point 4: The People of Potomac Yard Point 5: Crossroads of Transportation Point 6: The Rail Yard Hump Point 7: Potomac Yard In Transition Bus rapid transit from Crystal City to Potomac Yard opened in August 2014. Branded as Metroway , it travels in dedicated lanes along U.S. Route 1 . A Washington Metro infill station opened on May 19, 2023, after

3190-467: A short section of line that belongs to neither grid. Some systems increase the level of safety by the midpoint of the neutral section being earthed. The presence of the earthed section in the middle is to ensure that should the transducer controlled apparatus fail, and the driver also fail to shut off power, the energy in the arc struck by the pantograph as it passes to the neutral section is conducted to earth, operating substation circuit breakers, rather than

3300-539: A simpler alternative for moveable overhead power rails. Electric trains coast across the gaps. To prevent arcing, power must be switched off before reaching the gap and usually the pantograph would be lowered. Given limited clearance such as in tunnels , the overhead wire may be replaced by a rigid overhead rail. An early example was in the tunnels of the Baltimore Belt Line , where a Π section bar (fabricated from three strips of iron and mounted on wood)

3410-478: A tilted position into the horizontal position, connecting the conductor rails at the transition end section and the bridge together to supply power. Short overhead conductor rails are installed at tram stops as for the Combino Supra . Trams draw their power from a single overhead wire at about 500 to 750  V DC. Trolleybuses draw from two overhead wires at a similar voltage, and at least one of

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3520-701: A tramway. The tramway operated on 600–700 V DC and the railway on 15 kV AC . In the Swiss village of Oberentfelden , the Menziken–Aarau–Schöftland line operating at 750 V DC crosses the SBB line at 15 kV AC; there used to be a similar crossing between the two lines at Suhr but this was replaced by an underpass in 2010. Some crossings between tramway/light rail and railways are extant in Germany. In Zürich , Switzerland, VBZ trolleybus line 32 has

3630-570: Is Lehigh Valley region's third-largest employer. In August 2019, Amazon applied to have a liquor store in San Francisco , as a means to ship beer and alcohol within the city. In 2020, Amazon Fresh opened several physical stores in the U.S. and the United Kingdom . Amazon has a number of products and services available, including its digital assistant Alexa , Amazon Music , and Prime Video for music and videos respectively,

3740-580: Is a " social cataloging " website founded in December 2006 and launched in January 2007 by Otis Chandler, a software engineer, and entrepreneur, and Elizabeth Khuri. The website allows individuals to freely search Goodreads' extensive user-populated database of books, annotations, and reviews. Users can sign up and register books to generate library catalogs and reading lists. They can also create their groups of book suggestions and discussions. In December 2007,

3850-730: Is an electrical cable that is used to transmit electrical energy to electric locomotives , electric multiple units , trolleybuses or trams . The generic term used by the International Union of Railways for the technology is overhead line . It is known variously as overhead catenary , overhead contact line ( OCL ), overhead contact system ( OCS ), overhead equipment ( OHE ), overhead line equipment ( OLE or OHLE ), overhead lines ( OHL ), overhead wiring ( OHW ), traction wire , and trolley wire . An overhead line consists of one or more wires (or rails , particularly in tunnels) situated over rail tracks , raised to

3960-489: Is an American multinational technology company engaged in e-commerce , cloud computing , online advertising , digital streaming , and artificial intelligence . Founded in 1994 by Jeff Bezos in Bellevue, Washington , the company originally started as an online marketplace for books but gradually expanded its offerings to include a wide range of product categories, referred to as "The Everything Store". Today, Amazon

4070-438: Is an American video e-commerce live-streaming service created by Amazon Inc. to compete with live-streaming services. The service allows users to stream live videos promoting or sponsoring products. Users (mainly celebrities or Internet influencers ) have the option to livestream on Amazon and add tags to additionally add context to the products they're selling or promoting. Other users can join in and type in messages to send to

4180-422: Is briefly in contact with both wires). In normal service, the two sections are electrically connected; depending on the system this might be an isolator, fixed contact or a Booster Transformer. The isolator allows the current to the section to be interrupted for maintenance. On overhead wires designed for trolley poles, this is done by having a neutral section between the wires, requiring an insulator. The driver of

4290-664: Is considered one of the Big Five American technology companies, the other four being Alphabet , Apple , Meta , and Microsoft . The company has multiple subsidiaries , including Amazon Web Services , providing cloud computing; Zoox , a self-driving car division; Kuiper Systems , a satellite Internet provider; and Amazon Lab126 , a computer hardware R&D provider. Other subsidiaries include Ring , Twitch , IMDb , and Whole Foods Market . Its acquisition of Whole Foods in August 2017 for US$ 13.4 billion substantially increased its market share and presence as

4400-492: Is frequently used by websites and non-profits to provide a way for supporters to earn them a commission. Associates can access the Amazon catalog directly on their websites by using the Amazon Web Services (AWS) XML service. A new affiliate product, aStore, allows Associates to embed a subset of Amazon products within another website, or linked to another website. In June 2010, Amazon Seller Product Suggestions

4510-422: Is in use, standard sizes for contact wire are 100 and 150 mm . The catenary wire is made of copper or copper alloys of 70, 120 or 150 mm . The smaller cross sections are made of 19 strands, whereas the bigger has 37 strands. Two standard configurations for main lines consist of two contact wires of 100 mm and one or two catenary wires of 120 mm , totaling 320 or 440 mm . Only one contact wire

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4620-415: Is insufficient to guard against this as the pantograph briefly connects both sections. In countries such as France, South Africa, Australia and the United Kingdom, a pair of permanent magnets beside the rails at either side of the neutral section operate a bogie-mounted transducer on the train which causes a large electrical circuit-breaker to open and close when the locomotive or the pantograph vehicle of

4730-450: Is often used for side tracks. In the UK and EU countries , the contact wire is typically made from copper alloyed with other metals. Sizes include cross-sectional areas of 80, 100, 107, 120, and 150 mm . Common materials include normal and high strength copper, copper-silver, copper-cadmium, copper-magnesium, and copper-tin, with each being identifiable by distinct identification grooves along

4840-583: Is reportedly discussing a second multi-billion dollar investment in AI startup Anthropic, following its initial $ 4 billion investment. Amazon sells many products under its own brand names , including phone chargers, batteries, and diaper wipes. The AmazonBasics brand was introduced in 2009, and now features hundreds of product lines, including smartphone cases, computer mice, batteries, dumbbells, and dog crates. Amazon owned 34 private-label brands as of 2019. These brands account for 0.15% of Amazon's global sales, whereas

4950-421: Is set up so that the vehicle's pantograph is in continuous contact with one wire or the other. For bow collectors and pantographs, this is done by having two contact wires run side by side over the length between 2 or 4 wire supports. A new one drops down and the old one rises up, allowing the pantograph to smoothly transfer from one to the other. The two wires do not touch (although the bow collector or pantograph

5060-1029: Is used only on the Gornergrat Railway and Jungfrau Railway in Switzerland, the Petit train de la Rhune in France, and the Corcovado Rack Railway in Brazil. Until 1976, it was widely used in Italy. On these railways, the two conductors are used for two different phases of the three-phase AC, while the rail was used for the third phase. The neutral was not used. Some three-phase AC railways used three overhead wires. These were an experimental railway line of Siemens in Berlin-Lichtenberg in 1898 (length 1.8 kilometres (1.1 mi)),

5170-538: The Amazon Appstore for Android apps, the Kindle line of eink e-readers, Fire and Fire HD color LCD tablets. Audible provides audiobooks for purchase and listening. In September 2021, Amazon announced the launch of Astro , its first household robot, powered by its Alexa smart home technology. This can be remote-controlled when not at home, to check on pets, people, or home security. It will send owners

5280-539: The Nielsen BookScan service to verified authors. While the ASR has been the source of much speculation by publishers, manufacturers, and marketers, Amazon itself does not release the details of its sales rank calculation algorithm. Some companies have analyzed Amazon sales data to generate sales estimates based on the ASR, though Amazon states: Please keep in mind that our sales rank figures are simply meant to be

5390-577: The Richmond-Washington Company to manage traffic. This holding company controlled the Richmond, Fredericksburg and Potomac Railroad (RF&P), the new Alexandria Union Station , which opened in 1905, and the new switching yard—Potomac Yard—which opened on October 15, 1906. The booming "Pot Yard" attracted thousands of workers, who largely settled in the areas of Del Ray and St. Elmo. These subdivisions incorporated as

5500-525: The Whole Foods Market supermarket chain in 2017. It is the leading e-retailer in the United States with approximately US$ 178 billion net sales in 2017. It has over 300 million active customer accounts globally. Amazon saw large growth during the COVID-19 pandemic , hiring more than 100,000 staff in the United States and Canada. Some Amazon workers in the U.S., France, and Italy protested

5610-463: The tram or trolleybus must temporarily reduce the power draw before the trolley pole passes through, to prevent arc damage to the insulator. Pantograph-equipped locomotives must not run through a section break when one side is de-energized. The locomotive would become trapped, but as it passes the section break the pantograph briefly shorts the two catenary lines. If the opposite line is de-energized, this voltage transient may trip supply breakers. If

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5720-504: The 1500 V DC overhead of the railway and the 650 V DC of the trams, called a Tram Square. Several such crossings have been grade separated in recent years as part of the Level Crossing Removal Project . Athens has two crossings of tram and trolleybus wires, at Vas. Amalias Avenue and Vas. Olgas Avenue, and at Ardittou Street and Athanasiou Diakou Street. They use the above-mentioned solution. In Rome , at

5830-636: The Alexa Web Information Service. AWS later shifted toward providing enterprise services with Simple Storage Service (S3) in 2006, and Elastic Compute Cloud (EC2) in 2008, allowing companies to rent data storage and computing power from Amazon. In 2006, Amazon also launched the Fulfillment by Amazon program, which allowed individuals and small companies (called "third-party sellers") to sell products through Amazon's warehouses and fulfillment infrastructure. Amazon purchased

5940-447: The Amazon website and this may lead to an increase in sales. In particular, products that experience large jumps (up or down) in their sales ranks may be included within Amazon's lists of "movers and shakers"; such a listing provides additional exposure that might lead to an increase in sales. For competitive reasons, Amazon does not release actual sales figures to the public. However, Amazon has now begun to release point of sale data via

6050-521: The Hell's Gate Bridge boundary between Amtrak and Metro North 's electrifications) that would never be in-phase. Since a dead section is always dead, no special signal aspect was developed to warn drivers of its presence, and a metal sign with "DS" in drilled-hole letters was hung from the catenary supports. Occasionally gaps may be present in the overhead lines, when switching from one voltage to another or to provide clearance for ships at moveable bridges, as

6160-485: The Internet. Audible sells digital audiobooks , radio and television programs, and audio versions of magazines and newspapers. Through its production arm, Audible Studios, Audible has also become the world's largest producer of downloadable audiobooks. On January 31, 2008, Amazon announced it would buy Audible for about $ 300 million. The deal closed in March 2008 and Audible became a subsidiary of Amazon. Goodreads

6270-569: The Seattle area for its abundance of technical talent from Microsoft and the University of Washington , as well as its smaller population for sales tax purposes and the proximity to a major book distribution warehouse in Roseburg, Oregon . Bezos also considered several other options, including Portland, Oregon , and Boulder, Colorado . The company, originally named Cadabra, was founded in

6380-509: The U.S. and amazon.co.uk for UK) though some offer international shipping. Visits to amazon.com grew from 615 million annual visitors in 2008, to more than 2 billion per month in 2022. The e-commerce platform is the 12th most visited website in the world. In February, 2024, Amazon announced its first chatbot was first “Rufus” in the US and in July, it was widely available to all customers in

6490-565: The US. “Rufus” is now available in the US, India and the UK which helps the shoppers get product recommendations, get shopping list advice, compare products and see what other customers have responded to their specific questions. Results generated by Amazon's search engine are partly determined by promotional fees. The company's localized storefronts, which differ in selection and prices, are differentiated by top-level domain and country code : In 2000, US toy retailer Toys "R" Us entered into

6600-532: The United States. Amazon is also the global leader in research and development spending, with R&D expenditure of US$ 73 billion in 2022. Amazon has been criticized on various grounds, including but not limited to customer data collection practices, a toxic work culture , censorship , tax avoidance , and anti-competitive practices . Amazon was founded on July 5, 1994, by Jeff Bezos after he relocated from New York City to Bellevue, Washington , near Seattle , to operate an online bookstore. Bezos chose

6710-565: The arc either bridging the insulators into a section made dead for maintenance, a section fed from a different phase, or setting up a Backdoor connection between different parts of the country's national grid. On the Pennsylvania Railroad , phase breaks were indicated by a position light signal face with all eight radial positions with lenses and no center light. When the phase break was active (the catenary sections out of phase), all lights were lit. The position light signal aspect

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6820-541: The area began in the 1850s, though stymied by political concerns and by the American Civil War . The Alexandria and Washington Railroad began service on a new rail line between Long Bridge and Alexandria in 1857. Order to the region's mishmash of active and abandoned rail lines and stations did not come until the City Beautiful movement of the late 19th century. The 1901 Plan for Washington, D.C. ,

6930-595: The average for other large retailers is 18%. Other Amazon retail brands include Presto!, Mama Bear, and Amazon Essentials. Amazon derives many of its sales (around 40% in 2008) from third-party sellers who sell products on Amazon. Some other large e-commerce sellers use Amazon to sell their products in addition to selling them through their websites. The sales are processed through Amazon.com and end up at individual sellers for processing and order fulfillment and Amazon leases space for these retailers. Small sellers of used and new goods go to Amazon Marketplace to offer goods at

7040-481: The comments feature on customer reviews was rarely used ." The remaining review response options are to indicate whether the reader finds the review helpful or to report that it violates Amazon policies (abuse). If a review is given enough "helpful" hits, it appears on the front page of the product. In 2010, Amazon was reported as being the largest single source of Internet consumer reviews. When publishers asked Bezos why Amazon would publish negative reviews, he defended

7150-653: The company's decision to "run normal shifts" due to COVID-19's ease of spread in warehouses. In Spain, the company faced legal complaints over its policies, while a group of US Senators wrote an open letter to Bezos expressing concerns about workplace safety. On February 2, 2021, Bezos announced that he would step down as CEO to become executive chair of Amazon's board. The transition officially took place on July 5, 2021, with former CEO of AWS Andy Jassy replacing him as CEO. In January 2023, Amazon cut over 18,000 jobs, primarily in consumer retail and its human resources division in an attempt to cut costs. On November 8, 2023,

7260-612: The contact wire, cold drawn solid copper was used to ensure good conductivity . The wire is not round but has grooves at the sides to allow the hangers to attach to it. Sizes were (in cross-sectional area) 85, 100, or 150 mm . To make the wire stronger, 0.04% tin might be added. The wire must resist the heat generated by arcing and thus such wires should never be spliced by thermal means. The messenger (or catenary) wire needs to be both strong and have good conductivity. They used multi-strand wires (or cables) with 19 strands in each cable (or wire). Copper, aluminum, and/or steel were used for

7370-476: The controller into neutral and coast through. Trolleybus drivers had to either lift off the accelerator or switch to auxiliary power. In Melbourne , Victoria, tram drivers put the controller into neutral and coast through section insulators, indicated by insulator markings between the rails. Melbourne has several remaining level crossings between electrified suburban railways and tram lines. They have mechanical switching arrangements (changeover switch) to switch

7480-536: The converted garage of Bezos's house for symbolic reasons and was renamed to Amazon in November 1994. The Amazon website launched for public sales on July 16, 1995, and initially sourced its books directly from wholesalers and publishers. Amazon went public in May 1997. It began selling music and videos in 1998, and began international operations by acquiring online sellers of books in the United Kingdom and Germany. In

7590-514: The corporate mergers of the former separate railroad companies that used the yard to interchange freight cars, the need for Potomac Yard greatly diminished. It was determined by the RF&;P that the land was worth more than the need for yard switching. The PRR's old catenary was dismantled in the 1980s. The facility was identified as a toxic waste site in 1987. The RF&P finally decommissioned it in 1989. Plans for rehabilitation and redevelopment of

7700-786: The creation of the District of Columbia in 1791, and retroceded to Virginia in 1846. Its role as a transportation hub began when Congress chartered the Alexandria Canal Company in 1830. The canal, which opened on December 2, 1843, would connect the port of Alexandria with the end of the Chesapeake and Ohio Canal (completed 1850) in Georgetown via the Potomac Aqueduct Bridge . It would operate until abandoned in 1886. Railroad development in

7810-526: The crossing between Viale Regina Margherita and Via Nomentana, tram and trolleybus lines cross: tram on Viale Regina Margherita and trolleybus on Via Nomentana. The crossing is orthogonal, therefore the typical arrangement was not available. In Milan , most tram lines cross its circular trolleybus line once or twice. Trolleybus and tram wires run parallel in streets such as viale Stelvio, viale Umbria and viale Tibaldi. Some railways used two or three overhead lines, usually to carry three-phase current. This

7920-517: The future of the brownfield land . The City of Alexandria rejected the original mixed-use plan in 1992. Jack Kent Cooke , owner of the then Washington Redskins , unsuccessfully pushed for the construction of a new football stadium on the site. Seventy of the 400 acres (1.6 km) of the site were approved for retail use in 1995; the Potomac Yard Center, a 589,856-square-foot (54,799.4 m) strip mall anchored by big box stores ,

8030-546: The land have been a source of intense debate since then. At decommissioning, decades of industrial use had left the site contaminated with heavy metals and hydrocarbons, including diesel fuel . It was immediately declared a Superfund site. In 1995 the Environmental Protection Agency (EPA) approved RF&P's study and cleanup plan, and cleanup was declared completed by 1998. Various commercial and community interest groups came into conflict over

8140-451: The line is under maintenance, an injury may occur as the catenary is suddenly energized. Even if the catenary is properly grounded to protect the personnel, the arc generated across the pantograph can damage the pantograph, the catenary insulator or both. Sometimes on a larger electrified railway, tramway or trolleybus system, it is necessary to power different areas of track from different power grids, without guaranteeing synchronisation of

8250-482: The military railway between Marienfelde and Zossen between 1901 and 1904 (length 23.4 kilometres (14.5 mi)) and an 800-metre (2,600 ft)-long section of a coal railway near Cologne between 1940 and 1949. On DC systems, bipolar overhead lines were sometimes used to avoid galvanic corrosion of metallic parts near the railway, such as on the Chemin de fer de la Mure . All systems with multiple overhead lines have

8360-409: The natural 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 contact wire at regular intervals by vertical wires known as "droppers" or "drop wires". It is supported regularly at structures, by a pulley , link or clamp . The whole system is then subjected to mechanical tension . As

8470-402: The overhead conductor rail that runs across the entire span of the swing bridge. The gap is required for the swing bridge to be opened and closed. To connect the conductor rails together when the bridge is closed, there is another conductor rail section called "rotary overlap" that is equipped with a motor. When the bridge is fully closed, the motor of the rotary overlap is operated to turn it from

8580-435: The overhead line is limited due to the change in the height of the weights as the overhead line expands and contracts with temperature changes. This movement is proportional to the distance between anchors. Tension length has a maximum. For most 25 kV OHL equipment in the UK, the maximum tension length is 1,970 m (6,460 ft). An additional issue with AT equipment is that, if balance weights are attached to both ends,

8690-455: The pantograph as the train travels around the curve. The movement of the contact wire across the head of the pantograph is called the "sweep". The zigzagging of the overhead line is not required for trolley poles. For tramways , a contact wire without a messenger wire is used. Depot areas tend to have only a single wire and are known as "simple equipment" or "trolley wire". When overhead line systems were first conceived, good current collection

8800-457: The pantograph causes mechanical oscillations in the wire. The waves must travel faster than the train to avoid producing standing waves , which could break the wire. Tensioning the line makes waves travel faster, and also reduces sag from gravity. For medium and high speeds, the wires are generally tensioned by weights or occasionally by hydraulic tensioners. Either method is known as "auto-tensioning" (AT) or "constant tension" and ensures that

8910-411: The pantograph moves along under the contact wire, the carbon insert on top of the pantograph becomes worn with time. On straight track, the contact wire is zigzagged slightly to the left and right of the centre from each support to the next so that the insert wears evenly, thus preventing any notches. On curves, the "straight" wire between the supports causes the contact point to cross over the surface of

9020-484: The partnership in November 2019. Companies including IKEA and Birkenstock also stopped selling through Amazon around the same time, citing similar frustrations over business practices and counterfeit goods. In September 2017, Amazon ventured with one of its sellers JV Appario Retail owned by Patni Group which has recorded a total income of US$  104.44 million ( ₹ 759 crore ) in financial year 2017–2018. As of October 11, 2017 , AmazonFresh sold

9130-424: The phases. Long lines may be connected to the country's national grid at various points and different phases. (Sometimes the sections are powered with different voltages or frequencies.) The grids may be synchronised on a normal basis, but events may interrupt synchronisation. This is not a problem for DC systems. AC systems have a particular safety implication in that the railway electrification system would act as

9240-423: The popularity of a product sold on any Amazon locale. It is a relative indicator of popularity that is updated hourly. Effectively, it is a "best sellers list" for the millions of products stocked by Amazon. While the ASR has no direct effect on the sales of a product, it is used by Amazon to determine which products to include in its bestsellers lists. Products that appear in these lists enjoy additional exposure on

9350-432: The practice by claiming that Amazon.com was "taking a different approach ... we want to make every book available—the good, the bad and the ugly ... to let truth loose". There have been cases of positive reviews being written and posted by public relations companies on behalf of their clients and instances of writers using pseudonyms to leave negative reviews of their rivals' works. The Amazon sales rank (ASR) indicates

9460-522: The project, leaving National Landing as the only HQ2 site. Prior to Amazon's selection of National Landing, Virginia Tech had stated it would establish an "Innovation Campus" in the Alexandria portion of the neighborhood. English settlers built several plantations on the site in the 18th century. The land, much owned by the Swann and Daingerfield families, became part of Alexandria County, D.C. with

9570-519: The reactive upward pull of the tensioned wires lift the pulley so its teeth are well clear of a stop on the mast. The pulley can turn freely while the weights move up or down as the wires contract or expand. If tension is lost the pulley falls back toward the mast, and one of its teeth jams against the stop. This stops further rotation, limits the damage, and keeps the undamaged part of the wire intact until it can be repaired. Other systems use various braking mechanisms, usually with multiple smaller pulleys in

9680-411: The real name of the reviewer (based on confirmation of a credit card account) or which indicates that the reviewer is one of the top reviewers by popularity. As of December 16, 2020, Amazon removed the ability of sellers and customers to comment on product reviews and purged their websites of all posted product review comments. In an email to sellers Amazon gave its rationale for removing this feature: "...

9790-524: The report of the McMillan Commission , proposed consolidating the region's rail operations, including a new Washington Union Station , which was approved in 1903 and completed 1908, and a New Long Railroad Bridge (completed 1904). In accordance with the plan, the Pennsylvania Railroad (PRR), Baltimore and Ohio Railroad , Southern Railway , Chesapeake and Ohio Railway , Atlantic Coast Line Railroad , and Seaboard Air Line Railway formed

9900-405: The service in categories that Toys "R" Us had been granted exclusivity. In 2006, a court ruled in favor of Toys "R" Us, giving it the right to unwind its agreement with Amazon and establish its independent e-commerce website. The company was later awarded $ 51 million in damages. In 2001, Amazon entered into a similar agreement with Borders Group , under which Amazon would comanage Borders.com as

10010-423: The site had over 650,000 members, and over a million books had been added. Amazon bought the company in March 2013. Ring is a home automation company founded by Jamie Siminoff in 2013. It is primarily known for its WiFi powered smart doorbells , but manufactures other devices such as security cameras. Amazon bought Ring for US$ 1 billion in 2018. Overhead lines An overhead line or overhead wire

10120-554: The site is highlighted by a new Town Center. The plan also includes 1,900,000 square feet (180,000 m) of office space; a 625-room hotel; 135,000 square feet (12,500 m) of neighborhood retail space; and approximately 1,900 residential units. The plan for the Arlington site includes 2,800,000 square feet (260,000 m) of office space; a 625-room hotel; 100,000 square feet (9,300 m) of neighborhood retail space; and approximately 1000 residential units. The plan also calls for

10230-420: The stiffness of the spring for ease of maintenance. For low speeds and in tunnels where temperatures are constant, fixed termination (FT) equipment may be used, with the wires terminated directly on structures at each end of the overhead line. The tension is generally about 10 kN (2,200 lbf). This type of equipment sags in hot conditions and is taut in cold conditions. With AT, the continuous length of

10340-488: The strands. All 19 strands could be made of the same metal or a mix of metals based on the required properties. For example, steel wires were used for strength, while aluminium or copper wires were used for conductivity. Another type looked like it had all copper wires but inside each wire was a steel core for strength. The steel strands were galvanized but for better corrosion protection they could be coated with an anti-corrosion substance. In Slovenia , where 3 kV system

10450-454: The subsequent year, it initiated the sale of a diverse range of products, including music, video games, consumer electronics, home improvement items, software, games, and toys. In 2002, it launched Amazon Web Services (AWS), which initially focused on providing APIs for web developers to build web applications on top of Amazon's ecommerce platform. In 2004, AWS was expanded to provide website popularity statistics and web crawler data from

10560-514: The tension is virtually independent of temperature. Tensions are typically between 9 and 20  kN (2,000 and 4,500  lbf ) per wire. Where weights are used, they slide up and down on a rod or tube attached to the mast, to prevent them from swaying. Recently, spring tensioners have started to be used. These devices contain a torsional spring with a cam arrangement to ensure a constant applied tension (instead of varying proportionally with extension). Some devices also include mechanisms for adjusting

10670-554: The time suggested that Amazon planned to eventually roll out 300 to 400 bookstores around the country. All of its locations were closed in 2022 along with other retail locations under the "Amazon 4-Star" brand. In July 2016, the company announced that it was opening a 1,100,000 ft (335,280.0 m) square foot facility in Palmer Township in the Lehigh Valley region of eastern Pennsylvania . As of 2024, Amazon

10780-576: The town of Potomac in 1908, but were annexed by the City of Alexandria in 1930. Potomac Yard in its heyday was one of the busiest railyards in the Eastern United States, processing thousands of cars daily. The PRR extended its railway electrification program to Potomac Yard in 1935, marking its southernmost point. The Penn Central segment of the famous Tropicana Juice Train operated from here. The site reached capacity in 1937. After

10890-494: The train or tram and back to the feeder station through the steel wheels on one or both running rails. Non-electric locomotives (such as diesels ) 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 electromagnetic induction . Vehicles like buses that have rubber tyres cannot provide

11000-470: The tram wire. The tram's pantograph bridges the gap between the different conductors, providing it with a continuous pickup. Where the tram wire crosses, the trolleybus wires are protected by an inverted trough of insulating material extending 20 or 30 mm (0.79 or 1.18 in) below. Until 1946, a level crossing in Stockholm , Sweden connected the railway south of Stockholm Central Station and

11110-444: The trolleybus wires must be insulated from tram wires. This is usually done by the trolleybus wires running continuously through the crossing, with the tram conductors a few centimetres lower. Close to the junction on each side, the tram wire turns into a solid bar running parallel to the trolleybus wires for about half a metre. Another bar similarly angled at its ends is hung between the trolleybus wires, electrically connected above to

11220-406: The upper lobe of the contact wire. These grooves vary in number and location on the arc of the upper section. Copper is chosen for its excellent conductivity, with other metals added to increase tensile strength. The choice of material is chosen based on the needs of the particular system, balancing the need for conductivity and tensile strength. Catenary wires are kept in mechanical tension because

11330-499: The whole tension length is free to move along the track. To avoid this a midpoint anchor (MPA), close to the centre of the tension length, restricts movement of the messenger/catenary wire by anchoring it; the contact wire and its suspension hangers can move only within the constraints of the MPA. MPAs are sometimes fixed to low bridges, or otherwise anchored to vertical catenary poles or portal catenary supports. A tension length can be seen as

11440-490: The world's largest retailer outside of China, driven in large part by its paid subscription plan, Amazon Prime , which has close to 200 million subscribers worldwide. It is the second-largest private employer in the United States and the second-largest company in the World and in the U.S. by revenue as of 2024. As of October 2024, Amazon is the 12th-most visited website in the world and 84% of its traffic comes from

11550-505: Was completed in 1997. Other sections of Potomac Yard have since been slated for development as residential units, office space, parkland, and retail use. The Potomac Yard Complex by Crescent Resources is already under construction. One and Two Potomac Center was completed in November 2005 and houses several EPA offices. The southernmost portion of the Alexandria section is under construction as of August 2006. It includes two plans, one for Arlington and one for Alexandria. The Alexandria portion of

11660-402: Was launched to provide more transparency to sellers by recommending specific products to third-party sellers to sell on Amazon. Products suggested are based on customers' browsing history. Amazon allows users to submit reviews to the web page of each product. Reviewers must rate the product on a rating scale from one to five stars. Amazon provides a badging option for reviewers which indicates

11770-729: Was originally devised by the Pennsylvania Railroad and was continued by Amtrak and adopted by Metro North . Metal signs were hung from the catenary supports with the letters "PB" created by a pattern of drilled holes. A special category of phase break was developed in America, primarily by the Pennsylvania Railroad. Since its traction power network was centrally supplied and only segmented by abnormal conditions, normal phase breaks were generally not active. Phase breaks that were always activated were known as "Dead Sections": they were often used to separate power systems (for example,

11880-429: Was possible only at low speeds, using a single wire. To enable higher speeds, two additional types of equipment were developed: Earlier dropper wires provided physical support of the contact wire without joining the catenary and contact wires electrically. Modern systems use current-carrying droppers, eliminating the need for separate wires. The present transmission system originated about 100 years ago. A simpler system

11990-488: Was proposed in the 1970s by the Pirelli Construction Company, consisting of a single wire embedded at each support for 2.5 metres (8 ft 2 in) of its length in a clipped, extruded aluminum beam with the wire contact face exposed. A somewhat higher tension than used before clipping the beam yielded a deflected profile for the wire that could be easily handled at 400 km/h (250 mph) by

12100-468: Was used, with the brass contact running inside the groove. When the overhead line was raised in the Simplon Tunnel to accommodate taller rolling stock, a rail was used. A rigid overhead rail may also be used in places where tensioning the wires is impractical, for example on moveable bridges . In modern uses, it is very common for underground sections of trams, metros, and mainline railways to use

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