World Library  
Flag as Inappropriate
Email this Article

Kolkata Metro

कोलकाता मेट्रो रेल
Native name কলকাতা মেট্রো
Locale Kolkata, West Bengal, India
Transit type Rapid transit
Number of lines 1
1 under construction
Number of stations 24
Daily ridership over 650,000[1]
Chief executive H. K. Sharma, Chairman
Headquarters HRBC House, St. George's gate road Kolkata[2]
  • Kolkata Metro
Began operation 24 October 1984 (24 October 1984)
Operator(s) Kolkata Metro Rail Corporation Ltd. (KMRC)
Kolkata Metro zone of Indian Railways (Line 1 only)
System length 28.14 km (17.5 mi)
Track gauge 1,676 mm (5 ft 6 in)
(Indian gauge)
1,435 mm (4 ft 8 12 in)
(Standard gauge)
Electrification 750V DC through third rail

The Kolkata Metro or Calcutta Metro (Bengali: কলকাতা মেট্রো) is a metro system serving the city of Kolkata and the districts of South 24 Parganas and North 24 Parganas in the Indian state of West Bengal. It is the first Underground metro railway system in India. The network consists of one operational line (Line 1) and one under construction (Line 2), with four further lines in various stages of planning. It was the first such form of transport in India, opening for commercial services in 1984. It is the 17th zone of the Indian Railways system.


  • History 1
  • Construction 2
  • Kolkata Metro Master Plan 3
    • Further information 3.1
    • Major modifications 3.2
  • Network 4
    • Line 1 (North-South Metro) 4.1
    • Line 2 (East-West Metro) 4.2
    • Line 3 (Diamond Park-Joka-B.B.D.Bag Metro) 4.3
    • Line 4 (Noapara-Barasat Metro) 4.4
    • Line 5/1 (Noapara-Dakshineswar Strech) 4.5
    • Line 5 (Baranagar-Barrackpore Metro) 4.6
    • Line 6 (New Garia-Biman Bandar Metro) 4.7
  • Infrastructure 5
    • Rolling Stock 5.1
    • Stations and Electrification 5.2
    • Signalling and Frequency 5.3
  • Facilities and services 6
    • Tokens 6.1
    • Smart Card 6.2
    • Security 6.3
    • Departments 6.4
  • See also 7
  • References 8
  • External links 9


After Independence in 1947, the transport problem of Kolkata drew the attention of the city planners, the state government and also the government of India. It was soon realized that something had to be done and quickly in order to cope with the situation. It was Dr. Bidhan Chandra Roy, the then Chief Minister of West Bengal, who for the first time conceived the idea in 1949, of building an Underground Railway for Kolkata to try to solve the problems to some extent. A survey was done by a team of French experts but nothing concrete came of this. Efforts to solve the problem by augmenting the existing fleet of public transport vehicles hardly helped since roads account for only 4.2% of the surface area in Calcutta, and this is compared to 25% in Delhi and even 30% in other cities. With a view to finding out an alternative solution to alleviate the suffering of the Calcuttans, the Metropolitan Transport Project (Rlys) was set up in 1969. The MTP (Rlys), with help of Soviet specialists (Lenmetroproekt), prepared a master plan of providing five rapid-transit (metro) lines for the city of Kolkata, totalling a route length of 97.5 km in 1971, but only three were selected for construction. These were:

Of these, the highest priority was given to the busy north-south axis between Dum Dum and Tollygunge over a length of 16.45 km, and the work on this project was sanctioned on 1 June 1972. The foundation stone of the project was laid by Indira Gandhi, the then Prime Minister of India, on 29 December 1972 and the construction work started in 1973-74. From the start of construction, the project had to contend with several problems including, insufficient funds (until 1977-78), a shifting of underground utilities, court injunctions, and an irregular supply of vital materials. Despite the difficulties faced, services began on October 24, 1984, with the commissioning of a partial commercial service covering a distance of 3.40 km with five stations served in between Esplanade and Bhowanipur. The first metro was driven by Tapan Kumar Nath and Sanjoy Sil. The service was quickly followed by commuter services on another 2.15 km stretch in the north between Dum Dum and Belgachhia on November 12, 1984. The commuter service was extended up to Tollygunge on April 29, 1986 covering a further distance of 4.24 km making the service available over a distance of 9.79 km and covering 11 stations. However, the services on the north section were suspended with effect from October 26, 1992, as this isolated small section was little used. After a gap of more than eight years, the 1.62 km Belgachhia-Shyambazaar section, along with the Dum Dum-Belgachhia stretch, was opened on August 13, 1994. Another 0.71 km stretch from Esplanade to Chandni Chowk was commissioned shortly afterwards, on October 2, 1994. The Shyambazaar-Shobhabazar-Girish Park (1.93 km) and Chandni Chowk-Central (0.60 km) sections were opened on February 19, 1995. Services on the entire stretch of the Metro were introduced from September 27, 1995 by bridging the vital gap of 1.80 km in the middle. [3]

In the final stage, the extension of Line 1 to an elevated corridor from Tollygunge to New Garia was constructed and opened in two phases, Mahanayak Uttam Kumar to Kavi Nazrul in 2009 and Kavi Nazrul to Kavi Subhash in 2010. The latest extension constructed was the 2.59 km elevated corridor from Dum Dum to Noapara on 10 July 2013.


The North-South metro construction required several new technologies in the fields of civil, electrical, signaling and telecommunications engineering. Indian engineers backed by their own experience and helped by their studies abroad, used the following advanced technologies for the first time in India:

  • Cut-and-cover method of construction using diaphragm walls and sheet piles
  • Use of extensive decking to keep the traffic flowing over the cut section while construction continued underneath
  • Shield tunneling using compressed air and airlocks
  • Ballast-less track, using elastic fastenings, rubber pads, epoxy mortar and nylon inserts
  • Air-conditioning and ventilation systems for environmental control of stations and tunnels
  • Third rail current collection system for traction
  • Underground substations with dry type transformers and SF6 circuit breakers
  • Tunnel-train, VHF-radio communications system
  • Micro-processor based train control, and supervisory remote control system for substations
  • Automatic ticket vending and checking systems

All the new lines were constructed by the new state-of-art technologies. Most of the new links are elevated with only a few being underground. Unlike the North-South Corridor which used the cut-and-cover method for the whole underground route, the tunnels of the new lines were constructed using a tunnel-boring machine (TBM).

Kolkata Metro Master Plan

Kolkata Metro System Map

In 2010, the Railway Ministry announced plans for the construction of five new metro lines and an extension of the existing North-South corridor. These new projects are:

Further information

Kolkata Metro Railway - Official Site - for extention details

Major modifications

  • Construction of station at Noapara: A new 4-platform station has been constructed at Noapara. Commuters of Line 1 will be able to interchange trains going towards the Airport via Line 4 (Noapara-Barasat). For the time being only two platforms are in use, but once Line 4 gets started, all four platforms will become operational.
  • Upgrade of "Central" metro station: A subway is going to be constructed in the existing Central station to provide an interchange between Line 1 and Line 2. Commuters will have to pass through the subway to access the new station that will be constructed on the west side of the existing station.


Line First operational Last Extension Stations Length
Line 1 24 October 1984 10 July 2013 24 28.14 Noapara Kavi Subhash
Line 2 September 2015 12 14.67 Howrah Maidan Salt Lake Sector 5
Line 3 15 17.075 Diamond Park Mahakaran(BBD BAG)
Line 4 9 17.13 Noapara Barasat
Line 5 11 12.40 Baranagar Barrackpore
Line 5/1 03 4.11 Noapara Dakshineswar
Line 6 24 29.10 Kavi Subhash Airport
Total 90 120.25

Line 1 (North-South Metro)

Kolkata metro Railway,the oldest metro in India

Line 1 has a total length of 28 kilometres (17 mi) serving 24 stations of which 15 are underground. It has a combination of elevated, ground-level and underground lines and uses five and a half feet (1.67metres) of Indian gauge, a broad gauge rolling stock. It was the first underground railway to be built in India, with the first trains running in October 1984, and the full stretch that had been initially planned was completed and operational by February 1995. On 28 December 2010, it became the 17th zone of the Indian Railways.[4] The New Delhi Metro, which opened in 2002, is the second such urban metro rail network in India. It had benefitted from the expertise gained during the Kolkata metro construction. In being the country’s first metro and constructed as a completely indigenous process, the Kolkata Metro was more of a trial-and-error affair, in contrast to the Delhi Metro, which has also seen the involvement of numerous international consultants. As a result, it took nearly 23 years to completely construct a 17 km underground railway.[1]

  1. New Garia
  2. Shahid Khudiram
  3. Kavi Nazrul
  4. Gitanjali
  5. Masterda Surya Sen
  6. Netaji
  7. Tollygunge
  8. Rabindra Sarobar
  9. Kalighat
  10. Jatin Das Park
  11. Netaji Bhavan
  12. Rabindra sadan
  13. Maidan
  14. Park Street
  15. Esplanade
  16. Chandni Chowk
  17. Central
  18. Mahatma Gandhi Road
  19. Girish Park
  20. Shobhabazar Sutanuti
  21. Shyambazaar
  22. Belgachhia
  23. Dum Dum
  24. Noapara

Line 2 (East-West Metro)

East-West Metro, a 48745.8 rupees (INR) (US$779.9) project to connect Kolkata with Howrah by an underwater metro line was given the go-ahead by the central government.[5] The length will be 14.67 km (8.9 km underground and 5.77 km elevated). This line will be constructed and maintained by a separate body named Kolkata Metro Rail Corporation (KMRC). However, in January 2011 KMRC and the entire East West (EW) metro corridor, was taken over by the Ministry of Railways from the Ministry of Urban development and the state government of West Bengal. Now the EW Metro's majority stake is with the Indian Railways and the remainder is as a loan from the Japan Bank for International Cooperation.

The West Bengal government had earlier appointed Delhi Metro Rail Corporation Limited to conduct a feasibility study of the project, after which the government had to then put the project on hold due to funding issues. The underwater metro plan was thought of when the first metro service was inaugurated in Kolkata in 1984 by former Prime Minister Indira Gandhi. The route is to cover 12 stations and go under the river through a tunnel. The foundation stone was laid on 22 February 2009.

The construction of line 2 started in March 2009. The East-West Metro will run from Salt Lake Sector 5 (in the east) to Howrah Maidan (in the west). Trains will be air conditioned, and underground stations will be equipped with platform screen doors. It will run on standard (4 ft 8.5 in or 1,435 mm) gauge, unlike line 1, which runs on broad (5 ft 6 in or 1,676 mm) gauge.

Between Mahakaran and Howrah Station, the metro will run 1,500 ft (460 m) under the Hooghly River — the first underwater metro in India. The line will be elevated between Salt Lake Sector 5 and Yuva Bharati Krirangan, and the remaining stretch will be underground. Transfer stations will be located at Sealdah and Howrah.

The first phase is planned to be operational in September 2015.[6]

Line 3 (Diamond Park-Joka-B.B.D.Bag Metro)

A 16.72 km long metro line from Joka (in extreme South Kolkata) and BBD Bagh (in central Kolkata) is under construction. It is being built by RVNL and the tender has gone to Simplex Infrastructures.

Proposed stations on this route:[7]

  2. IIM 1.00 KM
  3. Joka 2.00 KM
  4. Thakurpukur 3.455 KM
  5. Sakherbazar 4.67 KM
  6. Behala Chowrasta 6.13 KM
  7. Behala Bazar 7.460 KM
  8. Taratala 8.50 KM
  9. Majerhat 9.74 KM
  10. Mominpur 10.755 KM
  11. Kidderpore 11.87 KM
  12. Victoria 14.025 KM
  13. Park Street (Intersection with Line 1) 15.29 KM
  14. Dharamtala 16.215 KM
  15. Mahakaran[Dalhousie) (Intersection with Line 2) 17.075 KM

The proposed Esplanade station will not to be the same as that of Line 1 (North-South Metro) but a completely different station. Park Street will serve as an interchange between Line 3 and Line 1.

Line 4 (Noapara-Barasat Metro)

The project to build an 18.5 km line from Noapara to Barasat via Netaji Subhas Chandra Bose International Airport[8] is sanctioned and construction work has commenced.

The proposed stations on this route are[9]

  1. Noapara (Intersection with Line 1) (Intersection with Line 5/1) 0.00 KM
  2. Dum Dum Cantonment 2.80 KM
  3. Jessore Road 5.08 KM
  4. Biman Bandar (Intersection with Line 6) 6.245 KM
  5. Birati 7.90 KM
  6. New Barrackpore 10.405 KM
  7. Madhyamgram 12.310 KM
  8. Hridaypur 14.80 KM
  9. Barasat 17.13 KM

Line 5/1 (Noapara-Dakshineswar Strech)

  1. Noapara (Intersection with Line 1) (0.00 KM )
  2. Baranagar (Intersection with Line 5) ( 2.38 KM)
  3. Dakshineswar (4.11 KM)

Line 5 (Baranagar-Barrackpore Metro)

The Baranagar-Barrackpore Metro (Line 5) (12.40 KM) will help people of North Suburbs to go to South Kolkata quickly. There will be 11 metro stations in this route. The stations are -

  1. Baranagar 0.00 KM (Intersection with Line 5/1)
  2. Kamarhati 1.20 KM
  3. Agarpara 2.80 KM
  4. Sodepur 4.20 KM
  5. Panihati 5.40 KM
  6. Subhash Nagar 6.50 KM
  7. Khardah 7.90 KM
  8. Tata Gate 8.80 KM
  9. Titagarh 10.10 KM
  10. Talpukur 11.40 KM
  11. Barrackpore 12.40 KM

Line 6 (New Garia-Biman Bandar Metro)

A connection between New Garia and the Airport (29.1 km) via E M Bypass, Saltlake and Rajarhat has started; it will help to reduce travel time between the southern fringes of Kolkata to Netaji Subhas Chandra Bose International Airport. The work on this New Garia-Airport line was inaugurated by Mamata Banerjee on 7 February 2011 with a project deadline of six years.[10] The link between Kavi Subhas (New Garia) and the airport, to be set up at a cost of Rs4 billion, will have 24 stations with the terminal Airport station being an underground one.

The stations, as declared of now, will be named after eminent personalities.[10]

  1. Kavi Subhash Metro Station (Intersection with Line 1) 0.00 KM
  2. Satyajit Ray Film and Television Institute 1.6 KM
  3. Mukundapur 3.0 KM
  4. Kalikapur 4.1 KM
  5. Ruby Hospital 5.1 KM
  6. VIP Bazar 6.40 KM
  7. Bantala 7.30 KM
  8. Science City 8.6 KM
  9. Beliaghata 9.5 KM
  10. Chingrighata 11.2 KM
  11. Nicco Park 12.6 KM
  12. Salt Lake Sector V (Intersection with Line 2) 13.9 KM
  13. Technopolis 15.1 KM
  14. Bidhan Nagar 16.2 KM
  15. Sub CBD-1 17.5 KM
  16. CBD-1 18.6 KM
  17. CBD-2 20.0 KM
  18. New Town 20.9 KM
  19. Convention Center 22.1 KM
  20. Sub CBD-2 23.30 KM
  21. City Centre 24.2 KM
  22. Rabindra Tirtha 25.1 KM
  23. VIP Road 26.7 KM
  24. Airport (Intersection with Line 4) 29.1 KM


Rolling Stock

3000 (new) AC Series coaches of Kolkata Metro
The rolling stock of Kolkata Metro Line 1 uses Indian gauge a broad gauge track which is manufactured by ICF, Chennai, and the electrical components are manufactured by NGEF, Bangalore. Initially, the rolling stock fleet was composed of 4-car rakes. Over the years there has been considerable expansion to the network, both underground and on elevated sections. With the increase in traffic, 8-car rake formation has become a standard for the Kolkata Metro. Presently there are 18 Non AC rakes and 13 AC rakes. Out of the 18 Non AC rakes, 11 will be phased out gradually since they have outlived their normal life of 25 years. The remaining 7 rakes are still in good condition so they will be refurbished and put into service in a phase manner. Until now, three types of trains have been used by Kolkata metro; these are - *BHEL Rake(1000 Series): 9 Rakes were manufactured by ICF, Chennai and were passed into service in the first phase when the metro initially ran from Esplanade to Bhawanipur (now Netaji Bhavan).[11] These trains were dark green in colour and had a yellow stripe at the bottom. Later the colour was changed to white with a dark blue stripe. Presently they are yellow with a wide brown band at the bottom.The rakes are usually numbered from B1 to B9 but two of these have been condemned.
Operating From 1984–Present
Length Per Coach 19.5 m
Length Per Train 156 m
Width Per Coach 2.74 m
Maximum Speed 55 km/h
Average Operating Speed 30–31 km/h
Voltage 750V DC
Electrification 3rd Rail
Coaches per Train 8
Capacity Per Coach 300 approx.[12]
Capacity Per Train 2400 approx.
Total Horse Power of Rake 3036 HP
Environment control Non AC with forced ventilation with washed and cooled air
  • NGEF Rake(2000 Series): 9 more rakes manufactured by ICF were put into operation in the next phase of service when the Metro rail expanded. These rakes were tougher and had higher acceleration than the previous ones. The colors of these trains were dark yellow with a maroon stripe at the bottom, later they were repainted in white with a maroon stripe and now they are white with a blue band at the bottom. The rakes are marked with 8N symbols
Operating From 1990–Present
Length Per Coach 19.5 m
Length Per Train 156 m
Width Per Coach 2.74 m
Maximum Speed 55 km/h
Average Operating Speed 30–31 km/h
Voltage 750V DC
Electrification 3rd Rail
Coaches per Train 8
Capacity Per Coach 300 approx.[12]
Capacity Per Train 2400 approx.
Total Horse Power of Rake 5221 HP
Environment control Non AC with forced ventilation with washed and cooled air
  • BHEL/Knorr Bremse AC(3000 Series): These are the latest trains that were passed into service in 2010, after the elevated corridor from Mahanayak Uttam Kumar to Kavi Nazrul was completed. Later, as the last extension from Kavi Nazrul to Kavi Subhash was finished, more 3000 Series rakes were introduced. These trains are manufactured by ICF in collaboration with BHEL and Knorr Bremse, Germany. They have microprocessor controlled temperature and humidity, LCD displays inside the motorman's cabins and multilingual electronic LED sign boards both inside and outside the train. Presently there are 13 (3000 series) rakes, which are operating on Line 1.
Operating From 2010–Present
Length Per Coach 20.3 m
Length Per Train 162.4 m
Width Per Coach 2.74 m
Maximum Speed 80 km/h
Average Operating Speed 35 km/h
Voltage 750V DC
Electrification 3rd Rail
Coaches per Train 8
Capacity Per Coach 392 [12]
Capacity Per Train 3136 approx.
Total Horse Power of Rake 5449 HP
Environment control Air Conditioned
  • CAF Melco: Spanish train manufacturing giant CAF will be providing 14 rakes for Line 2 at a cost of approximately 6 billion (US$97 million). Each train will have 6 coaches with a total capacity of 2068 passengers. The rakes will run on standard gauge track and the first few trains which will be manufactured in Spain are due to arrive in Kolkata in November 2014. The next order of rakes will be manufactured in India.

Stations and Electrification

Shobhabazar Sutanuti Metro Station,Calcutta
Shahid Khudiram Metro Station

Kolkata metro has 24 stations, 15 of which are underground, 7 are elevated and 2 stations are at grade. All the underground stations have island platforms except Park Street which has side platforms. While all the elevated stations have side platforms, Noapara has island platforms and since it will be the hub station for Line 1 and Line 4 it has 4 platforms having a length of 182m. The standard length of platforms in Kolkata Metro is 170m. The metro stations of Gitanjali & Netaji have the shortest platforms of 163m.[13] The average length between any two stations is 1.14 km. The shortest distance is 0.597 km between Central and Chandni Chowk, whereas the longest distance is 2.15 km between Dum Dum and Belgachhia. Since the electrification of Kolkata metro is of the 3rd Rail, 750V DC, electricity substations were built in Jatin Das Park, Central, Shyambazaar.[14] The type of tracks are ballast-less with M1A track fittings.

Signalling and Frequency

Kolkata metro trains operate on typical Indian Railways automatic signalling technology. A Route Relay Interlocking System has been provided at Mahanayak Uttam Kumar and Noapara carshed and are in operation to facilitate the prompt withdrawal and injection of rakes as well as performing shunting operations inside the carshed, required for maintenance purposes. Train Protection & Warning System(TPWS) is provided on the entire stretch of the Metro Railway. This system is designed to prevent collision caused by human (operator) error.[15] Train Describer System and Auto Train Charting have also been provided to help the operartion control centre to monitor and plan train movement on a real time basis.[16] The Metro operates between 0700 and 2145 hours, running every 10 minutes and every 5 minutes during peak hours on weekdays. Metro runs on Sundays between the hours of 1000 to 2145 hours. A number of 270 trains run during week days, 205 on Saturdays and 92 on Sundays.

Facilities and services

The Kolkata Metro provides special seats in every compartment which are reserved for women and senior citizens. The Kolkata Metro has also recently introduced functionality to support mobile signals in underground tunnels.[17] Metro stations are equipped with very large fans and few Metro rakes are air conditioned. The Kolkata Metro has introduced a smart card system.


After using the magnetic ticketing system for 27 years from 1984 to 2011, Kolkata Metro introduced radio-frequency identification (RFID) tokens from 2011. The old magnetic strip reader gates were replaced by new RFID readers.

Smart Card

After introducing RFID tokens, Kolkata metro introduced a Smart Card service. These smart cards are multi-programmable and commuters can opt for the various multi-ride schemes. To buy a new card a commuter needs to deposit INR100, which will be refunded after the card is returned in good condition, before its expiry date. A commuter can recharge the smart card for the sums of INR100, 200, 300, 500 or 1000 and receive 110% value on every recharge and the card is valid for a year. Kolkata metro also introduced smart card recharging machines, in Park Street station, on an experimental basis, where money could be credited onto the smart card by inserting INR100 notes into the machine and placing the card in its slot. Another type of Smart Card is the multi-ride card. These cards are bought on the basis of how many rides a commuter takes. The multi-ride smart cards are of 3 types. These were however withdrawn after the fare revision in November 2013. They were as follows:

  • Medium Multi-ride - 12 Rides
  • Limited Multi-ride - 40 and 60 Rides
  • Extended Multi-ride - 80 Rides

The most popular among daily commuters is the general smart card


All the stations are equipped with closed-circuit cameras, metal detectors, and X-ray baggage scanners, making the metro the safest form of transport in Kolkata.[18] The taking of photographs, eating, drinking and smoking are all prohibited on the metro premises.


Accounts, Electrical, Vigilance, Traffic, Engineering, Signal & Telecommunications, Personnel, Medical, Stores.[19]

See also


  1. ^ "Kolkata Metro's expansion plan to change life and times of commuters".  
  2. ^
  3. ^ "History". Retrieved 2013-07-18. 
  4. ^ "Kolkata Metro is now the 17th zone of Indian Railways".  
  5. ^ Underwater metro in Kolkata gets central nod
  6. ^ "Kolkata Metro inks purchase pact for coaches for East-West corridor - Business Line". Retrieved 2013-04-22. 
  7. ^ "Joka-BBD Bag Metro on the anvil". The Times Of India. 10 July 2010. 
  8. ^ Mandal, Sanjay (29 July 2009). "Circle of Metro commute". The Telegraph (Calcutta, India). 
  9. ^ "Dum Dum-Barrackpore Metro project awaits state nod". Retrieved 2012-07-07. 
  10. ^ "Salient Data on Rolling Stock". Retrieved 2013-06-30. 
  11. ^ a b c "First look: your swank AC Metro". Retrieved 2013-06-30. 
  12. ^ "Platforms at two stations shorter than stipulated". 26 May 2010. Retrieved 2013-06-30. 
  13. ^ "Existing Feautres". Retrieved 2013-06-30. 
  14. ^ "Automatic warning to make Metro safer". 3 March 2013. Retrieved 2013-06-30. 
  15. ^ "Existing Signalling System". Retrieved 2013-06-30. 
  16. ^ "রেলে এবার মোবাইল-সুবিধা". Retrieved 2012-07-24. 
  17. ^ "Kolkata metro to install x-ray baggage scanners". Daily News and Analysis. 5 October 2012. Retrieved 2012-11-07. 
  18. ^ "Metro Railway Kolkata - 2013 MBA". Retrieved 2013-04-22. 

External links

  • Official Website for line 1
  • Official Website for line 2
  • Urban Rail
  • Indian Railways
  • Sound of Kolkata Metro
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.