• Railways were first introduced to India in the year 1853from Mumbai to Thane
• Indian Railways Nationalized in 1951
• The country’s first railway, built by the Great Indian Peninsula Railway
• The Indian railway system is the largest in Asia and fourth in the world based on rail transport network size after the USA, China, and Russia
• It is a single undertaking in the country
• It has the second biggest electrified system in the world after Russia
• The number of stations at present is in between 8000 to 8500
• The total length of the Indian railway is 115,000 km
• At present Indian railway have 9549 locomotives 55,339 passenger services  vehicle 6560 other coaching vehicles and 239321 wagons
• Indian Railways is divided into 17 zones, which are further sub-divided into 68 divisions
• Each zone is headed by a general manager.

At present, it is one of the largest and busiest railway networks in the world, transporting over 1.8 crore passengers and more than 20 lakh tonnes of freight daily. It is the world's largest employer, with more than 14 lakh employees. 

Railways also make it possible to conduct multifarious activities like business, sightseeing, pilgrimage along with transportation of goods over longer distances. 

D. Allahabad

Train moving between Varanasi to chennai often covers stations like Satna, Katni, Jabalpur , Itarsi, Nagpur, Balharshah , Warangal, Hydrabad , Ongole etc.

D. Varanasi

Major cities on the route of Delhi Kolkata are :

1. Aligarh
2. Tundla
3. Kanpur
4. Allahabad
5. Mughal Sarai
6. Gaya
7. Dhanbad

B. Gorakhpur

The North Eastern Railway is one of the 16 railway zones in India. It is headquartered at Gorakhpur. The North Eastern Railway was formed on 14 April 1952 by combining two Railway systems the Oudh and Tirhut Railway and Assam Railway and the Cawnpore-Achnera Provincial State Railway of the Bombay, Baroda and Central India Railway. The Cawnpore-Barabanki Railway was transferred to the North Eastern Railway on 27 February 1953.

The gauge of the railway track is a clear minimum distance between the inner sides of two tracks. There broadly three types of gauge in India. They are 

• Frist underground metro rail was started in the year 1984 in Kolkata.  The rail served on a single line only, between Esplanade and Netaji Bhawan.
  
• In 2010 Kolkata underground metro railway was added to the present 16 railway zones and hence making Indian railway zones into 17.
  

Suburban rail is defined as a rail service between a central business district and suburbs that carry a large number of people on a daily basis. They usually have nine coaches or sometimes twelve to handle rush hour traffic.

Mumbai suburban rail is very developed. It is spread over 465 kilometres with 2342 trains carrying about 7 million people daily.

The busiest railway junction in eastern India is the Howrah junction railway station. It is the largest, oldest and busiest railway junction in eastern India with 23 platforms. It is located on the left bank of Hooghly River. A total of 274 passenger trains pass through this station making it the busiest railway station of India.

Construction of railways are influenced by a number of factors. Some of them are :

• Economic conditions: laying of railways is highly dependent on economic conditions of the country because it involves huge budget to lay and maintain railways. 
  
• Relief conditions play an important role in every developmental step including railways. 
  
• Distribution of population is another important influential factor because railways are laid keeping in mind the distribution of population. 
  

The only factor that do not influence is climatic conditions because irrespective of climatic conditions railways are laid and used by people.

Rajdhani Express and Shatabdi Express are express train services in India.

• Rajdhani and Shatabdi express trains are passenger trains and the fastest trains.
  
• Shatabdi express trains run short to medium distances while Rajdhani express covers long distances connecting metropolitans of the country.
  

The spread of railways from the 1850s created a new demand. Railways were essential for colonial trade and for the movement of imperial troops. From the 1860s, the railway network expanded rapidly. By 1890, about 25,500 km of track had been laid. In 1946, the length of the tracks had increased to over 765,000 km. 

• Integral Coach Factory (ICF) is the only manufacturer of rail coaches located in Chennai.
  
• Integral Coach Factory. Started in 1952, the Integral Coach Factory (ICF) is a factory for rail coaches located in Perambur, a suburb near Chennai.

Track gauge is the spacing of the rails on a railway track. Based on the width of gauge, it is classified into the standard gauge, minimum gauge, broad gauge, meter gauge, narrow gauge, medium gauge, etc. Metro rail is a rapid transit high-capacity public transport generally found in urban areas

• The headquarters of South Eastern Railway zone is in Kolkata. The zone comprises of 4 divisions.
• They are viz. Adra, Chakradharpur, Kharagpur and Ranchi. 

As of March 2017, the IR network spans 121,407 km (75,439 mi) of track length, while the route length is 67,368 km (41,861 mi). So option A is the closest.

The Golden Temple Express runs between Amritsar and Mumbai C.S.T. As we all know that the Golden temple is located at Amritsar. So, the train was named accordingly. Golden temple is the holiest gurudhwara of Sikhism.

The distribution pattern of the Railway network in the country has been largely influenced by physiographic, economic and administrative factors: The northern plains with their vast level land, high population density and rich agricultural resources provided the most favourable condition for their growth.

Himsagar ( Kanyakumari to Jammu Tawi ) is a train running between Kanyakumari and Jammu. Kanyakumari is located in the state of Tamil Nadu and Jammu is located in the state of Jammu & Kashmir. The two cities are located at a distance of 3714kms.

Broad gauge, meter gauge, narrow gauge indicate the width between two rails. The difference in their width is as follows:

• Broad gauge: 1.676 meters.
  
• Narrow gauge: 0.762 meters.
  
• Metre gauge: 1 meter.
  

Indian railways is one of the largest networks in India. It is divided into 16 railway zones and 7112 stations. These are managed and maintained by government of India through ministry of Railways.