Howrah–Chennai main line

The 1,661 km (1,032 mi) long trunk line has been treated in more detail in its sections:

1. Howrah–Kharagapur section (approximately 115 km (71 mi)
2. Kharagpur–Khurda Road section (approximately 363.1 km (225.6 mi)
3. Khurda Road–Visakhapatnam section (approximately 430 km (270 mi))
4. Nidadavole–Narsapuram section
5. Duvvada–Vijayawada section (approximately 350 km (220 mi)) (from Anakapalle south) South Coast Railway zone
6. Vijayawada–Gudur section (approximately 310 km (190 mi)) South Coast Railway zone
7. Gudur–Chennai section (approximately 140 km (87 mi)) (except Gudur Junction) Southern Railway zone

The Howrah–Chennai main line traverses the Eastern Coastal Plains crossing such major rivers as the Mahanadi, Godavari and Krishna. The coastal plains lying between the Eastern Ghats and the Bay of Bengal are fertile agricultural lands with high density of population.[1][2]

The Howrah–Delhi main line was the first trunk route in India connecting two metropolises. It was opened in 1866.[3] The second trunk route was Howrah–Prayagraj–Mumbai line, opened in 1870.[4] The Howrah–Nagpur–Mumbai line was opened in 1900 as the third trunk route in the country. Close on its heels was the Howrah–Madras main line in 1901.[5]

The first train service in southern India was operated from Royapuram/Vyasarpadi Jeeva in Chennai to Walajah Road, near Vellore, covering around 100 km (62 mi) long, and operated by Madras Railway Company, on 1 July 1856. Several other lines were also developed.[3] During the period 1893 to 1896, 1,287 km (800 mi) of the East Coast State Railway, from Vijayawada Junction to Cuttack was built and opened to traffic,[5][6] and construction of the Vijayawada–Madras link in 1899 enabled the through running of trains along the eastern coast of India.[4]Bengal Nagpur Railway was working on both the Howrah–Kharagpur and Kharagpur–Cuttack lines, completed the bridge over the Rupnarayan in 1900 and the Mahanadi in 1901, thus completing the through connection between Chennai and Kolkata.[5]

Howrah–Chennai Mail was the first train in South Eastern Railway to be hauled by a diesel engine (WDM-1) in 1965.[13]

The Howrah–Chennai route was completely electrified by 2005.[14]

The New Delhi–Chennai Central line (Grand Trunk route), of which the Vijayawada–Chennai section is a part, and Howrah–Nagpur–Mumbai line, of which the Howrah–Kharagpur section is a part, are classified as "Group A" lines which can take speeds up to 160 km/h. The Kharagpur-Vijayawada sector is classified as a Group B line which can take speeds up to 130 km/h.[15]

The main passenger train services along this line are the Howrah–Chennai Mail and the Coromandel Express. Howrah, Kharagpur, Balasore, Cuttack, Bhubaneswar, Brahmapur, Vizianagaram, Visakhapatnam, Rajahmundry, Eluru, Vijayawada, Nellore, Gudur and Chennai Central on this line are amongst the top hundred booking stations of Indian Railway.[16]

The Howrah–Chennai main line is a part of the golden quadrilateral. The routes connecting the four major metropolises (New Delhi, Mumbai, Chennai and Kolkata), along with their diagonals, known as the golden quadrilateral, carry about half the freight and nearly half the passenger traffic, although they form only 16 per cent of the length.[17]