Ghaziabad in the National Capital Region of India. It is one of the largest metro networks in the world. The network consists of six lines with a total length of 189. 63 kilometers (117. 83 mi) with 142 stations of which 35 are underground. It has a combination of elevated, at-grade, and underground lines and uses both broad gauge and standard gauge rolling stock.
Four types of rolling stock are used: Mitsubishi-ROTEM Broad gauge, Bombardier MOVIA, Mitsubishi-ROTEM Standard gauge, and CAF Beasain Standard gauge. Delhi Metro is being built and operated by the Delhi Metro Rail Corporation Limited (DMRC)under Akshay Mittal. As of November 2010, DMRC operates around 2,700 trips daily between 6:00 and 23:00 running with an interval of 2 minutes 30 seconds between trains at peak frequency.  The trains are mainly of four coaches, but due to an increase in passengers numbers, six-coach trains are also added on the Red Line (Dilshad Garden to Rithala), Yellow Line (Jahangirpuri to HUDA city center), Blue Line (Dwarka sec 21 to Vaishali/NOIDA city center) and Violet Line (Central Secretariat to Badarpur).  The power output is supplied by 25-kilovolt, 50 Hertz alternating current through overhead catenary. The metro has an average daily ridership of 1. 6 million commuters, and, as of July 2011, had carried over 1. 25 billion commuters since its inception. 10] The Delhi Metro Rail Corporation has been certified by the United Nations as the first metro rail and rail-based system in the world to get “carbon credits for reducing greenhouse gas emissions” and helping in reducing pollution levels in the city by 6. 3 lakh tonne every year.  Planning for the metro started in 1984 when the Delhi Development Authority and the Urban Arts Commission came up with a proposal for developing a multi-modal transport system for the city. The Government of India and the Government of Delhi jointly set up the Delhi Metro Rail Corporation (DMRC) in 1995.
Construction started in 1998, and the first section, on the Red Line, opened in 2002, followed by the Yellow Line in 2004, the Blue Line in 2005, its branch line in 2009, the Green and Violet Lines in 2010, and the Delhi Airport Metro Express in 2011. History Background The concept of a mass rapid transit for New Delhi first emerged from a traffic and travel characteristics study which was carried out in the city in 1969.  Over the next several years, many official committees by a variety of government departments were commissioned to examine issues related to technology, route alignment, and governmental jurisdiction.  In 1984, the Delhi Development Authority and the Urban Arts Commission came up with a proposal for developing a multi-modal transport system, which would consist of constructing three underground mass rapid transit corridors as well augmenting the city’s existing suburban railway and road transport networks.  While extensive technical studies and the raising of finance for the project were in progress, the city expanded significantly resulting in a twofold rise in population and a fivefold rise in the number of vehicles between 1981 and 1998.  Consequently, traffic congestion and pollution soared, as an increasing number of commuters took to private vehicles with the existing bus system unable to bear the load.  An attempt at privatizing the bus transport system in 1992 merely compounded the problem, with inexperienced operators plying poorly maintained, noisy, and polluting buses on lengthy routes, resulting in long waiting times, unreliable service, extreme overcrowding, unqualified drivers, speeding, and reckless driving.  To rectify the situation, the Government of India and the Government of Delhi jointly set up a company called the Delhi Metro Rail Corporation (DMRC) on March 5, 1995, with E. Sreedharan as the managing director.   Construction Physical construction work on the Delhi Metro started on October 1, 1998.  After the previous problems experienced by the Kolkata Metro, which was badly delayed and 12 times over budget due to “political meddling, technical problems, and bureaucratic delays”, the DMRC was given full powers to hire people, decide on tenders, and control funds.  The DMRC then consulted the Hong Kong MTR on rapid transit operation and construction techniques.  As a result, construction proceeded smoothly, except for one major disagreement in 2000, where the Ministry of Railways forced the system to use broad gauge despite the DMRC’s preference for standard gauge.  The first line of the Delhi Metro was inaugurated by Atal Behari Vajpayee, the then Prime Minister of India on December 24, 2002 and thus it became the second underground rapid transit system in India, after the Kolkata Metro.
The first phase of the project was completed in 2006 on budget and almost three years ahead of schedule, an achievement described by Business Week as “nothing short of a miracle”.   Network Main article: List of Delhi metro stations The Delhi Metro is being built in phases. Phase I completed 65. 11 km (40. 46 mi) of route length, of which 13. 01 km (8. 08 mi) is underground and 52. 10 km (32. 37 mi) surface or elevated. The inauguration of the Indraprastha–Barakhamba Road corridor of the Blue Line marked the completion of Phase I on October 27, 2006. 22] Phase II of the network comprises 128 km (80 mi) of route length and 79 stations and is fully completed, with the first section opened in June 2008, and the last line opened in August 2011.  Phases III (112 km) and IV (108. 5 km) are planned to be completed by 2015 and 2021 respectively, with the network pning 413 km (257 mi) by then. [25 Red Line Main article: Red Line (Delhi Metro) The Red Line was the first line of the Metro to be opened and connects Rithala in the west to Dilshad Garden in the east, covering a distance of 25. 09 kilometers (15. 59 mi). 27] It is partly elevated and partly at grade and crosses the Yamuna River between Kashmere Gate and Shastri Park stations.  The inauguration of the first stretch between Shahdara and Tis Hazari on December 24, 2002, caused the ticketing system to collapse due to the line being crowded to four times its capacity by citizens eager to have a ride.  Subsequent sections were inaugurated from Tis Hazari – Srinagar (later renamed Inderlok) on October 4, 2003, Inderlok – Rithala on March 31, 2004, and Shahdara – Dilshad Garden on June 4, 2008.   Yellow Line Main article: Yellow Line (Delhi Metro)
The Yellow Line was the second line of the Metro and was the first underground line to be opened.  It runs for 44. 36 kilometers (27. 56 mi) from north to south and connects Jahangirpuri with HUDA City Centre. The northern and southern parts of the line are elevated, while the central section through some of the most congested parts of Delhi is underground. The first section between Vishwa Vidyalaya and Kashmere Gate opened on December 20, 2004, and the subsequent sections of Kashmere Gate – Central Secretariat opened on July 3, 2005, and Vishwa Vidyalaya – Jahangirpuri on February 4, 2009.  This line also possesses the country’s deepest Metro station at Chawri Bazaar, situated 30 meters (98 ft) below ground level.  On 21 June 2010, an additional stretch from Qutub Minar to HUDA City Centre in Gurgaon was opened, initially operating separately from the mainline. However, Chhatarpur station on this line opened on August 26, 2010. Due to delay in acquiring the land for constructing the station, it was constructed using pre-fabricated structures in a record time of nine months and is the only station in the Delhi Metro network to be made completely of steel. 38] The connecting link between Central Secretariat and Qutub Minar opened on September 3, 2010.  Interchanges are available with the Red Line at Kashmere Gate station, Blue Line at Rajiv Chowk Station, Violet Line at Central Secretariat, and with the Indian Railways network at Delhi and New Delhi railway stations. Blue Line Main article: Blue Line (Delhi Metro) The Blue Line was the third line of the Metro to be opened, and the first to connect areas outside Delhi.  Partly overhead and partly underground, it connects Dwarka Sub City in the west with the satellite city of Noida in the east, covering a distance of 47. 4 kilometers (29. 5 mi).  The first section of this line between Dwarka and Barakhamba Road was inaugurated on December 31, 2005, and subsequent sections opened between Dwarka – Dwarka Sector 9 on April 1, 2006, Barakhamba Road – Indraprastha on November 11, 2006, Indraprastha – Yamuna Bank on May 10, 2009, Yamuna Bank – Noida City Centre on November 12, 2009, and Dwarka Sector 9 – Dwarka Sector 21 on October 30, 2010.  This line crosses the Yamuna River between Indraprastha and Yamuna Bank stations, and has India’s first extradosed bridge across the Northern Railways mainlines near Pragati Maidan.  A branch of the Blue line, inaugurated on January 8, 2010, takes off from Yamuna Bank station and runs for 6. 25 kilometers (3. 88 mi) up to Anand Vihar in east Delhi.  It was further extended up to Vaishali which was opened to the public on July 14, 2011.  A small stretch of 2. 76 kilometers (1. 71 mi) from Dwarka Sector 9 to Dwarka Sector 21 was inaugurated on October 30, 2010. 49] Interchanges are available with the Yellow Line at Rajiv Chowk station, and with the Indian Railways network at the Anand Vihar Railway Terminal.   Green Line Main article: Green Line (Delhi Metro) Opened in 2010, the Green Line was the first standard-gauge corridor of the Delhi Metro.  The fully elevated line connects Mundka with Inderlok, running for 15. 1 kilometer (9. 4 mi) mostly along Rohtak Road.  An interchange with the Redline is available at Inderlok station via an integrated concourse.  This line also has the country’s first standard-gauge maintenance depot at Mundka. 54]  Violet Line Main article: Violet Line (Delhi Metro) The Violet Line is the most recent line of the Metro to be opened, and the second standard-gauge corridor after the Green Line. The 20. 2 km (12. 6 mi) long line connects Badarpur to Central Secretariat, with 9 km (5. 6 mi) being overhead and the rest underground.  The first section between Central Secretariat and Sarita Vihar was inaugurated on October 3, 2010, just hours before the inaugural ceremony of the 2010 Commonwealth Games, and connects the Jawaharlal Nehru Stadium which is the venue for the opening and closing ceremonies of the event. 55] Completed in just 41 months, it includes a 100 m (330 ft) long bridge over the Indian Railways mainlines and a 167. 5 m (550 ft) long cable-stayed bridge across an operational road flyover, and connects several hospitals, tourist attractions, and a major industrial estate along its route.  Services are provided at intervals of 5 min. 
An interchange with the Yellow Line is available at Central Secretariat through an integrated concourse.  On January 14, 2011, the remaining portion from Sarita Vihar to Badarpur was opened for commercial service, adding three new stations to the network and marking the completion of the line. Airport Express The Airport Express line runs for 22. 7 km (14. 1 mi) from New Delhi Railway Station to Dwarka Sector 21, linking the Indira Gandhi International Airport. The line is operated, by the Delhi Airport Metro Express Pvt. Limited (DAMEL), a subsidiary of Reliance Infrastructure, the concessionaire of the line.  Constructed at a cost of [pic]2,885 crores (US$548. 15 million), the line has six stations (Dhaula Kuan and Delhi Aerocity became operational on August 15, 2011), with some featuring check-in facilities, parking, and eateries. 58] Rolling stock consists of six-coach trains operating at intervals of ten minutes and having a maximum speed of 135 km/h (84 mph).  Originally scheduled to open before the 2010 Commonwealth Games, the line failed to obtain the mandatory safety clearance and was opened on 24 February 2011, after a delay of around 5 months.  Finances  Funding The capital cost of Phases I and II has been estimated to be [pic]14,430 crores (US$2. 74 billion) at 2004 prices.  However, more recent estimates have placed the cost of construction at [pic]200 crores (US$38 million) per kilometer.  Thirty percent of the total investment for Phases I and II has been raised through equity capital with the Government of India (GoI) and Government of Delhi contributing equal shares, and approximately another 60 percent has been raised as either long-term or subordinate debt, through soft loans from the Japan Bank for International Cooperation.  The rest of the investment is proposed to be recovered from internal revenues through operations and property development.  The Metro also received [pic]1,914. 3 crore (US$363. 7 million) as grant-in-aid from various agencies for the financial year ending March 2009. 76] As of August 7, 2010, Delhi Metro has paid back an amount of [pic]567. 63 crore (US$107. 85 million), which includes loan amount for Phase I and interest amounts for Phases I and II, to the Japan International Cooperation Agency (JICA). 
Revenue and profits In 2007, the Delhi Metro claimed to be one of only five metro systems in the world that operated at a profit without government subsidies. This was enabled by keeping maintenance costs to a minimum and harnessing additional revenue from advertisements and property development, apart from ticket sales. 78] The Metro also generates revenue by leasing out its trains and stations for film shoots. Due to its increasing association with Delhi as an image of the city’s everyday life, it has been a popular filming location for production houses, and several films and advertisements have been shot on board.  Producers have to pay as much as [pic]1 lakh (US$1,900) for every hour of filming, besides a security deposit and insurance.  For the financial year ended March 2008, the Metro reported operating revenues of [pic]305. 27 crore (US$58 million) and a profit before tax of [pic]19. 8 crore (US$3. 8 million), which rose to [pic]723. 77 crore (US$137. 5 million) and [pic]90. 43 crore (US$17. 2 million) respectively for the financial year ended March 2009.  Operations Trains operate at a frequency of 3 to 4. 5 minutes between 6:00 and 23:00. Trains operating within the network typically travel at speeds below 80 km/h (50 mph) and stop about 20 seconds at each station. Automated station announcements are recorded in Hindi and English. Many stations have services such as ATMs, food outlets, cafes, and convenience stores.
Eating, drinking, smoking, and chewing of gum is prohibited in the entire system. The Metro also has a sophisticated fire alarm system for advanced warning in emergencies, and fire retardant material is used in trains as well as on the premises of stations.  Navigation information is available on Google Transit.  The first coach of every train is reserved for women.   Security Security on the Delhi Metro is handled by the Central Industrial Security Force (CISF), who have been guarding the system ever since they took over from the Delhi Police in 2007. [ 87] Closed-circuit cameras are used to monitor trains and stations, and feed from these is monitored by both the CISF and Delhi Metro authorities at their respective control rooms.  Over 3500 CISF personnel have been deployed to deal with law and order issues in the system, in addition to metal detectors, X-ray baggage inspection systems, and dog squads which are used to secure the system.  Intercoms are provided in each train car for emergency communication between the passengers and the Train operator. 90] Periodic security drills are carried out at stations and on trains to ensure the preparedness of security agencies in emergency situations.   Ticketing For the convenience of customers, Delhi Metro commuters have three choices for ticket purchase. The RFID tokens are valid only for a single journey on the day of purchase and the value depends on the distance traveled, with fares for a single journey ranging from [pic]8 (US$0. 15) to [pic]30 (US$0. 57). Fares are calculated based on the origin and destination stations using a fare chart. 92] A common ticketing facility for commuters traveling on Delhi Transport Corporation (DTC) buses and the Metro will be introduced in 2011.  Travelcards are available for longer durations and are most convenient for frequent commuters. They are valid for one year from the date of purchase or the date of the last recharge and are available in denominations of [pic]100 (US$1. 9) to [pic]800 (US$15. 2). A 10% discount is given on all travel made on it.  A deposit of [pic]50 (US$0. 95) needs to be made to buy a new card.  Tourist cards can be used for unlimited travel on the Delhi Metro network over short periods of time.
There are two kinds of tourist cards valid for one and three days respectively. The cost of a one-day card is [pic]100 (US$1. 9) and that of a three-day card is [pic]250 (US$4. 8), besides a refundable deposit of [pic]50 (US$0. 95) that must be paid at the time of purchasing the card.  As the network has expanded, high ridership in new trains have led to increasing instances of overcrowding and delays on the Delhi Metro.  To alleviate the problem, orders for new 6 coach trains have been placed and an increase in the frequency of trains has been proposed. 95] Infrequent, overcrowded and erratic feeder bus services connecting stations to nearby localities have also been reported as an area of concern.  In 2010, severe overcrowding on the Yellow Line, which connects the north and south campuses of Delhi University, was reported to be a reason for students missing or reporting late for classes.   Ridership Delhi Metro recorded the highest ever ridership figure of 2,066,925 on 20 August 2011, which surpassed the earlier record set on 01 August 2011, when 1,830,944 people traveled by the Metro. 100] Currently, DMRC has a pool of 200 train sets with 69 of these being six coach formations. At present; the Delhi Metro is operational on six lines where more than 2500 train trips are made each day traversing over 69000 KMs in a day. With Phase-III of the network expected to cover about 108 kilometers, the Delhi Metro network will become 295 kilometers by 2016 making it one of the fastest expanding Metro networks in the world carrying about 4 million (40 lakh) passengers. 
On October 19, 2008, a girder launcher and a part of the overhead Blue Line extension under construction in Laxmi Nagar, East Delhi collapsed and fell on passing vehicles underneath. Workers were lifting a 400-tonne concrete p of the bridge with the help of a crane when the launcher collapsed along with a 34 meters (112 ft) long p of the bridge on top of a Blueline bus killing the driver and a laborer.  On July 12, 2009, a portion of a bridge under construction collapsed when its launching girder lost balance as it was being erected at Zamrudpur, near East of Kailash, on the Central Secretariat – Badarpur corridor. Six people were killed and 15 others injured.  The day after, on July 13, 2009, a crane that was removing the debris collapsed, and with a bowling pin effect collapsed two other nearby cranes, injuring six.  On July 22, 2009, a steel beam fell on a worker at the under-construction Ashok Park Metro station, killing him.  Over a hundred people, including 93 workers, have died since work on the metro began in 1998.  Rolling stock The Metro uses the rolling stock of two different gauges.
Phase I lines use 1,676 mm (5. 499 ft) broad gauge rolling stock, while three Phase II lines use 1,435 mm standard gauge rolling stock.  Trains are maintained at seven depots at Khyber Pass and Sultanpur for the Yellow Line, Mundka for the Green Line, Najafgarh and Yamuna Bank for the Blue Line, Shastri Park for the Red Line, and Sarita Vihar for the Violet Line.  Broad gauge The broad gauge rolling stock is manufactured by two major suppliers. For Phase I, the rolling stock was supplied by a consortium of companies comprising Hyundai Rotem, Mitsubishi Corporation, and MELCO. The coaches were initially built in South Korea by ROTEM, then in Bangalore by BEML through a technology transfer arrangement.  These trains consist of four 3. 2-meter (10 ft) wide stainless steel lightweight coaches with vestibules permitting movement throughout their length and can carry up to 1500 passengers, with 50 seated and 330 standing passengers per coach.  The coaches are fully air-conditioned, equipped with automatic doors, microprocessor-controlled brakes, and secondary air suspension, and are capable of maintaining an average speed of 32 km/h (20 mph) over a distance of 1. 1 km (0. 68 mi).  The system is extensible up to eight coaches, and platforms have been designed accordingly.  The rolling stock for Phase II is being supplied by Bombardier Transportation, which has received an order for 614 cars worth approximately US$ 1100 million. 118] While initial trains were made in Germany and Sweden, the remainder will be built at Bombardier’s factory in Savli, near Vadodara.  These trains are a mix of four-car and six-car consists, capable of accommodating 1178 and 1792 commuters per train respectively.
The coaches possess several improved features like Closed Circuit Television (CCTV) cameras with eight-hour backup for added security, charging points in all coaches for cell phones and laptops, improved air conditioning to provide a temperature of 25 degrees Celsius even in packed conditions, and heaters for winter. 120]  Standard gauge The standard gauge rolling stock is manufactured by BEML at its factory in Bangalore. The trains are four-car consists of a capacity of 1506 commuters per train, accommodating 50 seated and 292 standing passengers in each coach.  These trains will have CCTV cameras in and outside the coaches, power supply connections inside coaches to charge mobiles and laptops, better humidity control, microprocessor-controlled disc brakes, and will be capable of maintaining an average speed of 34 km/h (21 mph) over a distance of 1. km (0. 68 mi).   Airport Express Eight 6-car trains supplied by CAF Beasain of Spain were imported.  CAF holds 5% equity in the DAME project, Reliance Infrastructure holds the remaining 95%.  The trains on this line are entirely different from the existing ones and have in-built noise reduction features for a noise-free ride with padded fabric seats. The coaches are equipped with LCD screens for the entertainment of the passengers and also provide flight information for the convenience of air travelers.
The trains are fitted with an event recorder that can withstand high levels of temperature and impact and the wheels have a flange lubrication system for less noise and better riding comfort.   Maglev On 7 December 2011, the government informed the Rajya Sabha that it was planning to introduce magnetic levitation wheel-less trains on the Delhi Metro. Minister of State for Urban Development Saugata Roy said: “The Delhi Metro proposes to introduce the wheel-less trains. The introduction of the Maglev technology of Metro connectivity by DMRC is only at a conceptual stage for the present. “ The Maglev technology uses magnetic levitation to suspend, guide, and propel mass rapid systems. Signaling and telecommunication The Delhi Metro uses cab signaling along with a centralized automatic train control system consisting of automatic train operation, Automatic Train Protection, and automatic train signaling modules.  A 380 MHz digital trunked TETRA radio communication system from Motorola is used on all 6 lines to carry both voice and data information.  For Line 3,4 Siemens Transportation Systems has supplied the electronic interlocking Sicas, the operation control system Vicos OC 500, and the automation control system LZB 700 M.  An integrated system comprising optical fiber cable, on-train radio, CCTV, and a centralized clock and public address system is used for telecommunication during train operations as well as emergencies.  For Line-1 and Line-2 ALSTOM has supplied signalling system and for line 5,6 Bombardier has supplied the signalling system.  Environment and aesthetics The Delhi Metro has won awards for environmentally friendly practices from organizations including the United Nations, RINA, and the International Organization for Standardization, becoming the second metro in the world, after the New York City Subway, to be ISO 14001 certified for environmentally friendly construction.  Most of the Metro stations on the Blue Line conduct rainwater harvesting as an environmental protection measure.
 It is also the first railway project in the world to earn carbon credits after being registered with the United Nations under the Clean Development Mechanism, and has so far earned 400,000 carbon credits by saving energy through the use of regenerative braking systems on its trains.  The Metro has been promoted as an integral part of community infrastructure, and community artwork depicting the local way of life has been put on display at stations. 136] Students of local art colleges have also designed decorative murals at Metro stations, while pillars of the viaduct on some elevated sections have been decorated with mosaic murals created by local schoolchildren.  The Metro station at INA Colony has a gallery showcasing artwork and handicrafts from across India, while all stations on the Central Secretariat – Qutub Minar section of the Yellow Line have panels installed on the monumental architectural heritage of Delhi.