Airports in India

More than 20 international airports are located within the Republic of India. These include:

• Bengaluru International Airport, Bangalore
• Calicut International Airport, Kozhikode
• Chatrapati Shivaji International Airport, Mumbai
• Chennai International Airport, Chennai
• Cochin International Airport, Cochin
• Coimbatore Airport, Coimbatore
• Dr. Babasaheb Ambedkar International Airport, Nagpur
• Indira Gandhi International Airport, Delhi
• Mangalore International Airport, Mangalore
• Netaji Subhash Chandra Bose International Airport, Kolkata
• Raja Sansi International Airport, Amritsar
• Rajiv Gandhi International Airport, Hyderabad
• Sardar Vallabhbhai Patel International Airport, Ahmedabad
• Trivandrum International Airport, Thiruvanthapuram

The Indira Gandhi International Airport and the Chatrapati Shivaji International Airport handle more than half of the air traffic in South Asia. Besides these airports several other domestic airports are located in India.

In total, there are more than 334 (2002 est.) civilian airports in India - 238 with paved runways and 108 with unpaved runways.

Airports - with paved runways (2007 est.)

10,000 ft (3,047 m) or more: 18

8,000 to 9,999 ft (2,438 to 3,047 m): 52

5,000 to 7,999 ft (1,524 to 2,437 m): 75

3,000 to 4,999 ft (914 to 1,523 m): 84

Under 3,000 ft (914 m): 21

Total: 250

[edit] Airports - with unpaved runways (2007 est.)

10,000 ft (3,047 m) or more: 1

8,000 to 9,999 ft (2,438 to 3,047 m): 1

5,000 to 7,999 ft (1,524 to 2,437 m): 7

3,000 to 4,999 ft (914 to 1,523 m): 40

Under 3,000 ft (914 m): 47

Total: 96

Heliports (2007 est.)

30

Nomenclature

Trains are sorted into various categories which dictate the number of stops along their route, the priority they enjoy on the network, and the fare structure. Each express train is identified by a four-digit —the first digit indicates the zone that operates the train, the second the division within the zone that controls the train and is responsible for its regular maintenance and cleanliness, and the last two digits are the train's serial number.

For super-fast trains, the first digit is always '2', the second digit is the zone, the third is the division and only the last digit is the serial number within the division. Trains travelling in opposite directions along the same route are usually labelled with consecutive numbers. However, there is considerable variation in train numbers and some zones, such as Central Railway, has a less systematic method for numbering trains. Most express trains also have a unique name attached to them which are usually exotic and are taken from landmarks, famous people, rivers and so on. Some notable examples are:

1. Charminar Express between Hyderabad and Chennai, named after the Charminar monument in Hyderabad.
2. Ashram Express between Ahmedabad and New Delhi, after Mahatma Gandhi's Sabarmati Ashram
3. Gitanjali Express between Mumbai CST and Howrah (Kolkata), after Rabindranath Tagore's famous work.
4. Parasuram Express between Mangalore and Thiruvananthapuram, after Parasurama.
5. Prayag Raj Express between Allahabad and New Delhi, after Prayag, a sacred pilgrimage spot and the ancient name of Allahabad.
6. Lal Bagh Express between Bangalore and Chennai, after the famous Lal Bagh botanical gardens in Bangalore.
7. Godavari Express between Hyderabad and Visakhapatnam after the Godavari River in South India.
8. Nilgiri (Blue Mountain) Express between Chennai and Coimbatore after the Nilgiri hills.
9. Purshottam Express (New Delhi-Puri)
10. Kashi Vishwanath Express (New Delhi-Varanasi)
11. Mangla Express
12. Bagh Express (Howrah-Kathgodam)
13. Ala Hazarat Express (Bareilly-Bhuj)

Traction

As of March 2007, 17,810 kilometres (11,067 mi) of the total 63,465 km (39,435 mi) route length is electrified. Most places use 25,000 V AC through overhead catenary delivery. A major exception is the entire Mumbai section, which uses 1,500 V DC. This is currently undergoing change to the 25,000 V system, and is scheduled for completion by 2008. Another exception is the Kolkata Metro, which uses 750 V DC delivered through a third rail.

Traction voltages are changed at two places close to Mumbai. Central Railway trains passing through Igatpuri switch from AC to DC using a neutral section that may be switched to either voltage while the locomotives are decoupled and swapped. Western Railway trains switch power on the fly, in a section between Virar (DC) and Vaitarna (AC), where the train continues with its own momentum for about 30 m through an unelectrified section of catenary called a dead zone. All electric engines and EMUs operating in this section are the necessary AC/DC dual system type (classified "WCAM" by Indian Railways).

Signalling systems

The Indian Railways makes use of colour signal lights, but in some remote areas of operation, the older semaphores and discs-based signalling (depending on the position or colour) are still in use. Except for some high-traffic sections around large cities and junctions, the network does not use automatic block systems. Safety therefore depends completely on the skill and vigilance of the personnel operating the individual signals and the drivers.

Coloured signalling makes use of multi-coloured lighting and in many places is automatically controlled. There are three modes:

• Two aspect signalling which makes use of a red (bottom) and green (top) lamp
• Three aspect signalling which makes use of an additional amber lamp in the centre
• Four (multiple) aspect signalling makes use of four lamps, the fourth is amber and is placed above the other three.

Multiple aspect signals, by providing several intermediate speed stages between 'clear' and 'on', allow high-speed trains sufficient time to brake safely if required. This becomes very important as train speeds rise. Without multiple-aspect signals, the stop signals have to be placed very far apart to allow sufficient braking distance and this reduces track utilisation. At the same time, slower trains can also be run closer together on track with multiple aspect signals.

Semaphores make use of a mechanical arm to indicate the line condition. Several subtypes are used:

• Two aspect lower quadrant
• Three aspect modified lower quadrant
• Multiple aspect upper quadrant
• Disc-based: These signals are located close to levers used to operate points. They are all two-aspect signals.

Indian locomotive

Indian locomotive fleet consists electric and diesel engines. Steam engines are no longer used, except for heritage trains. Engines are also called "locos".

In India, locomotives are classified according to their track gauge, motive power, the work they are suited for and their power or model number. The class name includes this information about the locomotive. It comprises 4 or 5 letters. The first letter denotes the track gauge. The second letter denotes their motive power (Diesel or Electric) and the third letter denotes the kind of traffic for which they are suited (goods, passenger, mixed or shunting).

One of the earliest pictures of railways in India

The fourth letter used to denote locomotives' chronological model number. However, from 2002 a new classification scheme has been adopted. Under this system, for newer diesel locomotives, the fourth letter will denote their horsepower range. Electric locomotives don't come under this scheme and even all diesel locos aren't covered. For them this letter denotes their model number as usual.

A locomotive may sometimes have a fifth letter in its name which generally denotes a technical variant or subclass or subtype. This fifth letter indicates some smaller variation in the basic model or series, perhaps different motors, or a different manufacturer. With the new scheme for classifying diesel locomotives (as mentioned above) the fifth item is a letter that further refines the horsepower indication in 100 hp increments: 'A' for 100 hp, 'B' for 200 hp, 'C' for 300 hp, etc. So in this scheme, a WDM-3A refers to a 3100 hp loco, while a WDM-3F would be a 3600 hp loco.

Highways

Main article: Indian highways

India has a network of National Highways connecting all the major cities and state capitals. As of 2005, India has a total of 65,569 km of National Highways, of which 4,885 km are classified as expressways. Most highways are 2 laned, while in some better developed areas they may broaden to 4 lanes. Close to big cities, highways can even be 8 laned.

All the highways are metalled. In most developed states the roads are smooth, however in less developed states and in sparsely populated areas, highways are riddled with potholes. Very few of India's highways are constructed of concrete, the most notable being the Mumbai-Pune Expressway.

Highways form the economic backbone of the country. Highways have facilitated development along the route and many towns have sprung up along major highways.

In recent years construction has commenced on a nationwide system of multi-lane highways, including the Golden Quadrilateral expressways which link the largest cities in India.

A bus service Srinagar Jammu and Kashmir) - Muzaffarabad (Pakistan controlled Kashmir, part of what India calls 'Pakistan-occupied Kashmir'), with one bus service every two weeks, at the same time in both directions, opened on 7 April 2005.

Length: total - 3,319,644 km; paved - 1,517,077 km; unpaved - 1,802,567 km (1999 est.)

Highways

India has a network of National Highways connecting all the major cities and state capitals. As of 2005, India has a total of 65,569 km of National Highways, of which 4,885 km are classified as expressways. Most highways are 2 laned, while in some better developed areas they may broaden to 4 lanes. Close to big cities, highways can even be 8 laned.

All the highways are metalled. In most developed states the roads are smooth, however in less developed states and in sparsely populated areas, highways are riddled with potholes. Very few of India's highways are constructed of concrete, the most notable being the Mumbai-Pune Expressway.

Highways form the economic backbone of the country. Highways have facilitated development along the route and many towns have sprung up along major highways.

In recent years construction has commenced on a nationwide system of multi-lane highways, including the Golden Quadrilateral expressways which link the largest cities in India.

A bus service Srinagar Jammu and Kashmir) - Muzaffarabad (Pakistan controlled Kashmir, part of what India calls 'Pakistan-occupied Kashmir'), with one bus service every two weeks, at the same time in both directions, opened on 7 April 2005.

Length: total - 3,319,644 km; paved - 1,517,077 km; unpaved - 1,802,567 km (1999 est.)