Air traffic control
Air traffic control is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through controlled airspace, can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions and expedite the flow of air traffic, provide information and other support for pilots. In some countries, ATC is operated by the military. To prevent collisions, ATC enforces traffic separation rules, which ensure each aircraft maintains a minimum amount of empty space around it at all times. Many aircraft have collision avoidance systems, which provide additional safety by warning pilots when other aircraft get too close. In many countries, ATC provides services to all private and commercial aircraft operating within its airspace. Depending on the type of flight and the class of airspace, ATC may issue instructions that pilots are required to obey, or advisories that pilots may, at their discretion, disregard; the pilot in command is the final authority for the safe operation of the aircraft and may, in an emergency, deviate from ATC instructions to the extent required to maintain safe operation of their aircraft.
Pursuant to requirements of the International Civil Aviation Organization, ATC operations are conducted either in the English language or the language used by the station on the ground. In practice, the native language for a region is used. In 1920, Croydon Airport, London was the first airport in the world to introduce air traffic control. In the United States, air traffic control developed three divisions; the first of air mail radio stations was created in 1922 after World War I when the U. S. Post Office began using techniques developed by the Army to direct and track the movements of reconnaissance aircraft. Over time, the AMRS morphed into flight service stations. Today's flight service stations do not issue control instructions, but provide pilots with many other flight related informational services, they do relay control instructions from ATC in areas where flight service is the only facility with radio or phone coverage. The first airport traffic control tower, regulating arrivals and surface movement of aircraft at a specific airport, opened in Cleveland in 1930.
Approach/departure control facilities were created after adoption of radar in the 1950s to monitor and control the busy airspace around larger airports. The first air route traffic control center, which directs the movement of aircraft between departure and destination was opened in Newark, NJ in 1935, followed in 1936 by Chicago and Cleveland; the primary method of controlling the immediate airport environment is visual observation from the airport control tower. The tower is a windowed structure located on the airport grounds. Air traffic controllers are responsible for the separation and efficient movement of aircraft and vehicles operating on the taxiways and runways of the airport itself, aircraft in the air near the airport 5 to 10 nautical miles depending on the airport procedures. Surveillance displays are available to controllers at larger airports to assist with controlling air traffic. Controllers may use a radar system called secondary surveillance radar for airborne traffic approaching and departing.
These displays include a map of the area, the position of various aircraft, data tags that include aircraft identification, speed and other information described in local procedures. In adverse weather conditions the tower controllers may use surface movement radar, surface movement guidance and control systems or advanced SMGCS to control traffic on the manoeuvring area; the areas of responsibility for tower controllers fall into three general operational disciplines: local control or air control, ground control, flight data / clearance delivery—other categories, such as Apron control or ground movement planner, may exist at busy airports. While each tower may have unique airport-specific procedures, such as multiple teams of controllers at major or complex airports with multiple runways, the following provides a general concept of the delegation of responsibilities within the tower environment. Remote and virtual tower is a system based on air traffic controllers being located somewhere other than at the local airport tower and still able to provide air traffic control services.
Displays for the air traffic controllers may be live video, synthetic images based on surveillance sensor data, or both. Ground control is responsible for the airport "movement" areas, as well as areas not released to the airlines or other users; this includes all taxiways, inactive runways, holding areas, some transitional aprons or intersections where aircraft arrive, having vacated the runway or departure gate. Exact areas and control responsibilities are defined in local documents and agreements at each airport. Any aircraft, vehicle, or person walking or working in these areas is required to have clearance from ground control; this is done via VHF/UHF radio, but there may be special cases where other procedures are used. Aircraft or vehicles without radios must respond to ATC instructions via aviation light signals or else be led by vehicles with radios. People working on the airport surface have a communications link through which they can communicate with ground control either by handheld radio or cell phone.
Ground control is vital to the smooth operation of the airport, because this position impacts th
Brown Line (CTA)
The Brown Line of the Chicago "L" system, is an 11.4-mile route with 27 stations between Chicago's Albany Park neighborhood and downtown Chicago. It runs above ground and is entirely grade-separated, it is the third-busiest'L' route, with an average of 63,481 passengers boarding each weekday in 2017. Before CTA lines were color-coded in 1993, the Brown Line was known as the Ravenswood Route. Accordingly, the Kimball-Belmont shuttle service was called the Ravenswood Shuttle; the Brown Line begins on the northwest side of Chicago, at the Kimball terminal in Albany Park, where there is a storage yard and servicing shop for the trains to the east of the passenger station. From there, trains operate over street level tracks between Leland and Eastwood Avenues to Rockwell Street ramp up to the elevated structure for the rest of the trip; the trains on the street-level section are powered by third rail rather than overhead catenary, a decision that exposes wayward pedestrians to the risk of electrocution.
A fatal accident in 1977 involving a intoxicated Korean immigrant who attempted to urinate on the third rail at the Kedzie station resulted in a famous Illinois Supreme Court decision in 1992 affirming a verdict of $1.5 million against CTA. After the Damen station, the route turns south, about one-half block parallel and west of Metra's Union Pacific North railroad line and Ravenswood Avenue to a point south of the Addison station. Here the route turns east again and runs parallel to Roscoe Street past Sheffield Avenue where it once again turns south at Clark Junction to join the four-track North Side elevated line in Lakeview. From just north of Belmont station south to Armitage and Red Line trains operate side-by-side, with Purple Line Express trains sharing the tracks with the Brown Line during weekday rush hours. Brown and Purple Line trains run on the outermost tracks serving five stops, while Red Line trains run on the innermost tracks making only two stops. South of the Armitage station and Purple Line trains continue southward towards the Chicago Loop on elevated tracks which zigzags its way through the neighborhoods of Lincoln Park and Near North Side stopping at Sedgwick and Chicago/Franklin.
Running over Franklin Wells Street, a stop is made at the Merchandise Mart before crossing the Chicago River on the upper level of the Wells Street Bridge before joining the Loop Elevated at Lake Street. Operating counter-clockwise, Brown Line trains operate around the Loop on the Outer track via Wells-Van Buren-Wabash-Lake, serving all Loop stations, before the return trip back north to the Kimball terminal. There are three sections of the Brown Line which includes the Ravenswood Branch that connects from Kimball Avenue station to Belmont Avenue station. Another is the North Side Main Line which connects from Belmont Avenue station to the Merchandise Mart before entering the Loop; the Brown Line enters the loop going counter-clockwise from Washington/Wells to Clark/Lake and exits the loop, heading towards the Kimball Avenue station. The Brown Line operates between Kimball and the Loop weekdays and Saturdays from 4 a.m. to 1:30 a.m. and on Sundays from 5 a.m. to 1:30 a.m. The Brown Line Shuttle service runs only between Belmont between 1:30 a.m. and 2:25 a.m..
At Belmont, southbound riders can transfer to the 24-hour Red Line. On weekdays, service runs between three and eight minutes during rush hour, seven to eight minutes during midday six to twelve minutes during nighttime. On weekends, early morning service operates every fifteen minutes increases to seven to eight minutes on Saturdays during the day and ten minutes on Sundays during the day at nighttime every ten to twelve minutes. Late night service operates every fifteen minutes until the end of service, although late night trips from Kimball to Belmont stations operate every half hour Monday thru Saturday nights. During morning rush hour, several Brown Line trains bound for the Loop continue toward the Orange Line after stopping at the Harold Washington Library station; the Brown Line is operated with the 3200-series railcars. The Brown Line operate using four cars at other times on weekdays and all day on weekends and eight cars during weekday rush hours; the Brown Line's 3200-series cars are to remain in service on the line until at least the late 2020s, where they will be replaced by the new 7000-series cars if all options are picked up, otherwise the Brown Line's 3200-series cars will remain in service on the line until the 2030s if the options are not picked up.
In the meantime, CTA is in the process of overhauling the 3200-series cars with color LED destination signs, new air conditioning systems, rebuilt propulsion systems, passenger door motors, wheel/axle assemblies. The 3200-series rehabilitation began in 2015 and was completed in 2018; that year, some of the Brown Line's 3200-series cars will be transferred to the Blue Line, with some of the Orange Line's 2600-series cars being transferred to the Brown Line. Beginning March 30, 2008, the Brown Line began running eight cars during rush hours, since all of the reopened or renovated stations have been rebuilt to accommodate eight cars. Prior to this, although ridership warranted eight cars on the Brown Line during weekday rush hours, most stations on the line couldn't berth longer than six cars. Six cars are standard on the Brown Line
Clark/Lake is a Chicago'L' station located at 100/124 West Lake Street in Chicago's Loop district, is accessed from the James R. Thompson Center and 203 North LaSalle building, it is one of the most complex stations on the'L' system, comprising an elevated station and a subway station. The elevated station is serviced by the Brown, Orange and Purple Lines, while the subway platform is serviced by the Blue Line. In December 2014 it had an average of 17,644 weekday passenger entrances, making it the second busiest station in the'L' system; the Richard J. Daley Center, Chicago City Hall, Chicago Title and Trust Center are served by the station, it is the busiest station on the Loop Elevated, the second-busiest station on the'L' system as of December 2014. This station has been recognized as the station with the most pickpockets by ABC 7 Chicago. Clark/Lake is a super station consisting of two stations; the original elevated station opened on September 22, 1895 as one of three stations on the Lake Street Elevated Railroad's "Wabash extension".
This extension became the Lake Street leg of the Union Loop when it was completed in 1897. The subway station opened as Lake Transfer on February 25, 1951. From 1988 to 1992, the elevated station was reconstructed, with its main entrance in the James R. Thompson Center; this allows transfers between the elevated station and the subway station without leaving the paid area, so the stations were combined into a single station. Due to this, it is the one station; the Blue Line serves the subway station while the Green Line stops at both sides of the elevated station, Orange and Purple Line trains stop at the Inner Loop platform, Brown Line trains stop at the Outer Loop platform. CTA 22 Clark 24 Wentworth 134 Stockton/LaSalle Express 135 Clarendon/LaSalle Express 136 Sheridan/LaSalle Express 156 LaSalle Media related to Clark/Lake at Wikimedia Commons Clark/Lake on CTA website Historic American Engineering Record No. IL-1-E, "Union Elevated Railroad, Clark Street Station" Clark Street entrance to elevated line from Google Maps Street View Lake Street entrance to Thompson Center from Google Maps Street View Wells Street entrance to subway from Google Maps Street View
Chicago the City of Chicago, is the most populous city in Illinois, as well as the third most populous city in the United States. With an estimated population of 2,716,450, it is the most populous city in the Midwest. Chicago is the principal city of the Chicago metropolitan area referred to as Chicagoland, the county seat of Cook County, the second most populous county in the United States; the metropolitan area, at nearly 10 million people, is the third-largest in the United States, the fourth largest in North America and the third largest metropolitan area in the world by land area. Located on the shores of freshwater Lake Michigan, Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed and grew in the mid-nineteenth century. After the Great Chicago Fire of 1871, which destroyed several square miles and left more than 100,000 homeless, the city made a concerted effort to rebuild; the construction boom accelerated population growth throughout the following decades, by 1900 Chicago was the fifth largest city in the world.
Chicago made noted contributions to urban planning and zoning standards, including new construction styles, the development of the City Beautiful Movement, the steel-framed skyscraper. Chicago is an international hub for finance, commerce, technology, telecommunications, transportation, it is the site of the creation of the first standardized futures contracts at the Chicago Board of Trade, which today is the largest and most diverse derivatives market gobally, generating 20% of all volume in commodities and financial futures. O'Hare International Airport is the one of the busiest airports in the world, the region has the largest number of U. S. highways and greatest amount of railroad freight. In 2012, Chicago was listed as an alpha global city by the Globalization and World Cities Research Network, it ranked seventh in the entire world in the 2017 Global Cities Index; the Chicago area has one of the highest gross domestic products in the world, generating $680 billion in 2017. In addition, the city has one of the world's most diversified and balanced economies, not being dependent on any one industry, with no single industry employing more than 14% of the workforce.
Chicago's 58 million domestic and international visitors in 2018, made it the second most visited city in the nation, behind New York City's approximate 65 million visitors. The city ranked first place in the 2018 Time Out City Life Index, a global quality of life survey of 15,000 people in 32 cities. Landmarks in the city include Millennium Park, Navy Pier, the Magnificent Mile, the Art Institute of Chicago, Museum Campus, the Willis Tower, Grant Park, the Museum of Science and Industry, Lincoln Park Zoo. Chicago's culture includes the visual arts, film, comedy and music jazz, soul, hip-hop and electronic dance music including house music. Of the area's many colleges and universities, the University of Chicago, Northwestern University, the University of Illinois at Chicago are classified as "highest research" doctoral universities. Chicago has professional sports teams in each of the major professional leagues, including two Major League Baseball teams; the name "Chicago" is derived from a French rendering of the indigenous Miami-Illinois word shikaakwa for a wild relative of the onion, known to botanists as Allium tricoccum and known more as ramps.
The first known reference to the site of the current city of Chicago as "Checagou" was by Robert de LaSalle around 1679 in a memoir. Henri Joutel, in his journal of 1688, noted that the eponymous wild "garlic" grew abundantly in the area. According to his diary of late September 1687:...when we arrived at the said place called "Chicagou" which, according to what we were able to learn of it, has taken this name because of the quantity of garlic which grows in the forests in this region. The city has had several nicknames throughout its history such as the Windy City, Chi-Town, Second City, the City of the Big Shoulders, which refers to the city's numerous skyscrapers and high-rises. In the mid-18th century, the area was inhabited by a Native American tribe known as the Potawatomi, who had taken the place of the Miami and Sauk and Fox peoples; the first known non-indigenous permanent settler in Chicago was Jean Baptiste Point du Sable. Du Sable arrived in the 1780s, he is known as the "Founder of Chicago".
In 1795, following the Northwest Indian War, an area, to be part of Chicago was turned over to the United States for a military post by native tribes in accordance with the Treaty of Greenville. In 1803, the United States Army built Fort Dearborn, destroyed in 1812 in the Battle of Fort Dearborn and rebuilt; the Ottawa and Potawatomi tribes had ceded additional land to the United States in the 1816 Treaty of St. Louis; the Potawatomi were forcibly removed from their land after the Treaty of Chicago in 1833. On August 12, 1833, the Town of Chicago was organized with a population of about 200. Within seven years it grew to more than 4,000 people. On June 15, 1835, the first public land sales began with Edmund Dick Taylor as U. S. Receiver of Public Monies; the City of Chicago was incorporated on Saturday, March 4, 1837, for several decades was the world's fastest-growing city. As the site of the Chicago Portage, the city became an important transportation hub between the eastern and western United States.
Chicago's first railway and Chicago Union Railroad, the Illi
Quincy station (CTA)
Quincy is a rapid transit station on the Chicago Transit Authority's'L' system. It is located between the LaSalle/Van Buren stations in the Loop; the station is located above the intersection of Quincy Street and Wells Street in downtown Chicago, Illinois. Having opened in 1897, it is one of the oldest surviving stations on the'L' system. Designed by Alfred M. Hedley from wood and stamped metal, Quincy opened on October 3, 1897, it retained much of its original surroundings over the years and is considered one of "150 great places in Illinois" by the American Institute of Architects. The station is located in the South Loop Financial District and is the closest CTA rail station to the Willis Tower one block west, it is close to Union Station, the terminal for several Metra and Amtrak routes and about three blocks west of Quincy, although the Clinton station on the Blue Line is closer. Quincy is an elevated station, located above Quincy Street between Adams Street and Jackson Boulevard, it features two side platforms and station houses, one on the west to serve the Outer Loop track, one on the east to serve the Inner Loop track.
Turnstiles for fare payment are located in the station houses on the platform level. The station once had a transfer bridge; this means it is not possible to change from one platform to the other without paying another fare or asking for employee assistance. There are auxiliary exits to both Adams and Jackson on the Inner Loop platform, while the Outer Loop only has an auxiliary exit to Adams. Both platforms are designed to handle the longest the CTA'L' system can run. From 1985 to 1988, Quincy was restored to an appearance; some materials such as signage were changed, although several of the station's features are original to its 1897 opening. A renovation project began at the station in 2016 and was completed in December 2018; the renovation added two new elevators to the station to make it accessible for people with disabilities, other improvements include new stairs and new lights. The station remained open during the project; the project was completed in December 2018. In normal operation, the station is serviced by the Brown and Pink Lines.
During weekday rush hours, the Purple Line stops here. Brown Line trains stop at the Outer Loop platform, while all other lines stop at the Inner Loop platform. In addition to'L' trains, the station provides service to several CTA bus routes: the 1 Bronzeville/Union Station, 7 Harrison, 28 Stony Island, 37 Sedgwick, 126 Jackson, 134 Stockton/LaSalle Express, 135 Clarendon/LaSalle Express, 136 Sheridan/LaSalle Express, 151 Sheridan, 156 LaSalle. Historic American Engineering Record No. IL-1-A, "Union Elevated Railroad, Quincy Street Station" Quincy/Wells Station Page at Chicago-'L'.org CTA - Train schedules: Brown Purple Orange PinkRidership figures, 2009 Adams Street entrance from Google Maps Street View Quincy Street entrance from Google Maps Street View Jackson Boulevard entrance from Google Maps Street View
An elevated railway is a rapid transit railway with the tracks above street level on a viaduct or other elevated structure. The railway may be broad gauge, standard gauge, narrow gauge, light rail, monorail, or a suspension railway. Elevated railways are used in urban areas where there would otherwise be a large number of level crossings. Most of the time, the tracks of elevated railways that run on steel viaducts can be seen from street level; the earliest elevated railway was the London and Greenwich Railway on a brick viaduct of 878 arches, built between 1836 and 1838. The first 2.5 miles of the London and Blackwall Railway was on a viaduct. During the 1840s there were other schemes for elevated railways in London that did not come to fruition. From the late 1860s onward elevated railways became popular in US cities; the New York West Side and Yonkers Patent Railway operated with cable cars from 1868 to 1870, thereafter locomotive-hauled. This was followed by the Manhattan Railway in 1875, the South Side Elevated Railroad and the elevated lines of the Boston Elevated Railway.
The Chicago transit system itself is known as "L", short for "elevated". The Berlin Stadtbahn and the Vienna Stadtbahn are mainly elevated; the first electric elevated railway was the Liverpool Overhead Railway, which operated through Liverpool docks from 1893 until 1956. In London, the Docklands Light Railway is a modern elevated railway that opened in 1987 and, has expanded; the trains are automatic. Another modern elevated railway is Tokyo's driverless Yurikamome line, opened in 1995. Most monorails are elevated railways, such as the Disneyland Monorail System, the Tokyo Monorail, the Sydney Monorail, the KL Monorail, the Las Vegas Monorail, the São Paulo Monorail. Many maglev railways are elevated. During the 1890s there was some interest in suspension railways in Germany, with the Schwebebahn Dresden, the Wuppertal Schwebebahn. H-Bahn suspension railways were built in Dortmund and Düsseldorf airport, 1975; the Memphis Suspension Railway opened in 1982. The Shonan Monorail and the Chiba Urban Monorail in Japan, despite their names, are suspension railways too.
Suspension railways are monorail. People mover or automated people mover is a type of driverless grade-separated, mass-transit system; the term is used only to describe systems that serve as loops or feeder systems, but is sometimes applied to more complex automated systems. Similar to monorails, Bombardier Innovia APM technology uses only one rail to guide the vehicle along the guideway. APMs are common at airports and effective at helping passengers reach their gates. Several elevated APM systems at airports including the PHX Sky Train at Phoenix Sky Harbor International Airport. Berlin U-Bahn Chicago "L" Copenhagen Metro Hamburg U-Bahn Lahore Metro Manila Light Rail Transit System Miami Metrorail New York City Subway Philadelphia's Market–Frankford Line Rapid Metro Gurgaon Line 3 Scarborough, a medium capacity metro rail line in Toronto, Canada BTS Skytrain, two elevated rapid transit lines in Bangkok, Thailand SkyTrain, British Columbia, Canada. Sydney Metro Northwest Line in Sydney, Australia Vienna U-Bahn Wenhu line, Taiwan Wuppertal Suspension Railway Hyderabad Metro All Lines in Hyderabad, IndiaDisused: Boston Elevated Railways - Atlantic Avenue Elevated, Charlestown Elevated, Washington Street Elevated, Causeway Street Elevated Elevated railways operated by the Interborough Rapid Transit Company and Brooklyn Rapid Transit Company in New York City Liverpool Overhead Railway AirTrain JFK, a people mover at and around John F. Kennedy International Airport, New York City, New York, United States ATL Skytrain, a people mover at Hartsfield–Jackson Atlanta International Airport, Georgia, United States Changi Airport Skytrain, an inter-terminal people mover at Changi International Airport in Singapore Detroit People Mover, an urban transit people mover in Detroit, United States H-Bahn, an inter-terminal automated people mover in Dortmund and Dusseldorf, Germany MIA Mover, a people mover at Miami International Airport, Florida, United States PHX Sky Train, a people mover at Phoenix Sky Harbor International Airport, Arizona, United States Tubular Rail, trackless elevated train.
UC San Diego Blue Line extension will be aerial light rail
State/Lake is an'L' station serving the CTA's Brown, Orange and Purple Lines. It is an elevated station with two side platforms, located in the Chicago Loop at 200 North State Street; the CTA offers the Lake subway station on the Red Line. State/Lake station opened on September 22, 1895, as part on the Lake Street Elevated Railroad's extension into the Chicago Loop that became the north side of the Union Loop. State/Lake is the last station on this section of the Loop to retain many of its original features. One of a series of videos "shot on iPhone 6" to feature in a 2015 Apple advertising campaign features the short journey between Randolph/Wabash and State/Lake shot in time lapse. CTA 2 Hyde Park Express 6 Jackson Park Express 10 Museum of Science and Industry 29 State 36 Broadway 62 Archer 146 Inner Drive/Michigan Express Historic American Engineering Record No. IL-1-H, "Union Elevated Railroad, State-Lake Station" State Street entrance from Google Maps Street View