Sealdah South section
Sealdah South section consists of a set of four lines which connect the  station in Kolkata with its southern suburbs and with the South 24 Parganas district of West Bengal, India. It is a part of the Kolkata Suburban Railway and is under the jurisdiction of the Sealdah railway division of the Eastern Railway zone of Indian Railways. It is linked to the Sealdah Main and North section via the Kankurgachi Chord line at  and via the Kolkata Circular Railway at . It also connects to the Kolkata Dock System Railway (KDS Railway) at  and  respectively. Services
The Sealdah South section consists of four lines:

 Sealdah–Diamond Harbour line ()
 Budge Budge branch line ()
 Canning branch line ()
 Namkhana branch line ()

The section is primarily a suburban section with a total of 334 daily services and 288 Sunday services serving the four lines of the section. A majority of the services are served by 12-car EMU rakes from the Sonarpur EMU Carshed. They are also served with a few 9-car EMU rakes from Narkeldanga EMU Carshed. There are many "Galloping local" services which only stop at important stations of a line. The Gangasagar mela, which attracts thousands of pilgrims during Makar Sankranti in mid-January, and is held in Sagar Island is approached through the Namkhana branch line of this section. and  railway stations serve as handy rail heads for travel to the mela. Eastern Railway runs a lot of special trains for the mela to cope with the increase in passenger traffic. There also are special trains from  to  via  and . The line has major interchange stations at  and  for the Circular line and at  and  with the Line 1 of Kolkata Metro. The under construction Line 2 and Line 3 of Kolkata Metro will provide major interchange stations at Sealdah and Majerhat as well. A new metro line from New Garia to Baruipur has been proposed as well. This section connects to the Kolkata Port, via the KDS Railway, from where major freight commodities like containers, coal and fertilizers are loaded and transferred throughout the Indian Railways network. History

Sealdah–Canning line 
The Calcutta and South-Eastern Railway (CSER) was formed in 1859 to connect Calcutta with  on the Matla River. It constructed and completed the  long line on 15 May 1863. It was the first railway track on the eastern bank of the Hooghly River and ran from what was then the Beliaghata railway station (presently ) to  on the Matla River via  and . In 1868, CSER having suffered extensive losses due to floods and other problems, sold the line to the Indian government (management then being leased to the Eastern Bengal Railway) and the company was dissolved in March 1870. Thus the line became a part of the Southern section of the Eastern Bengal Railway. Post partition of India in 1947 and re-organisation of railway zones in 1952, the entire Southern section of Eastern Bengal Railway was amalgamated under the Sealdah division of Eastern Railway. Sonarpur–Diamond Harbour line 
While multiple feasibility reports and proposals, beginning from 1839, were made for the construction of a railway line between Calcutta and Diamond Harbour, no action were taken on these. Finally in 1883, a  branch line to Diamond Harbour via  and Magrahat was constructed from  on the Sealdah–Canning line of the Eastern Bengal Railway. This line, from Sealdah to Diamond Harbour, then became the main line of the Southern section of the Eastern Bengal Railway. A small  branch line was constructed in 1883, from Diamond Harbour to Hara Fort near the Hooghly River to transport goods and military supplies as well. Ballygunge–Budge Budge line 
The Budge Budge branch line was initially sanctioned in 1886 as a line to connect  with the Kidderpore Docks. Sanction to an extension to Budge Budge was given in 1888 and the whole of  long line from  to  via  was opened on 1890 by the Eastern Bengal Railway. The Calcutta Port Commissioners' Railway (CPCR) built a branch line from Kidderpore Docks to Majerhat on 1893. It further constructed a branch line from the subsidiary marshaling yard at  to King George's Dock (renamed to Netaji Subhas Dock in 1973) in 1928. Baruipur–Lakshmikantapur–Namkhana line 
In 1928, a  long line from  on the Diamond Harbour branch line to  via  was constructed by the Eastern Bengal Railway and became a branch line of its Southern section. In an effort to give access to remote areas and promote new growth areas, the  long Lakshmikantapur–Namkhana line project was sanctioned in 1987-88 amongst other projects. The line was extended up to Kulpi by 1992 and was completed till Kakdwip by 2001. The Kakdwip–Namkhana section was completed by 2004. Kalighat–Falta Railway 

The Kalighat–Falta Railway (KFR) was a  long narrow gauge (762 mm) railway line constructed by the Kalighat–Falta Railway Company, and operated as a part of McLeod's Light Railways, opening to traffic on 28 May 1917 from Gholeshapur (near Kalighat) to Falta. Gholeshapur was connected to Majerhat junction on the Eastern Bengal Railway on 1920. The railway line was closed on 1955 due to ever increasing losses. The tracks were dismantled and the land was reclaimed to build a road, now called James Long Sarani, in Behala. Electrification
The Sealdah South section lines are fully electrified with 25 kV AC overhead system. The electrification process was started in 1965 from  to  line and the other lines in this division with the different phases and completed up to 1966 from that time the whole division is also fully electrified. EMU Carshed 
The Sealdah South section is primarily served by 12-car EMU rakes from the Sonarpur EMU Carshed. They are also served with a few 9-car EMU rakes from Narkeldanga EMU Carshed. While the section was initially served by the Narkeldanga EMU carshed which opened on 1963, a need for a dedicated EMU carshed for the section led to the construction of the Sonarpur EMU carshed in 1978. This reduced the inconvenience faced by the overburdened Narkeldanga EMU car shed. As of November 2021, the Sonarpur carshed had 32 12-car EMU rakes which exclusively served the Sealdah South section. The Narkeldanga carshed had 29 9-car EMU rakes, a few of which served the Sealdah South section mostly via the Circular line, while rest served the Sealdah Main and North section. Routes and stations

Stations
Names in bold indicate that the station is a galloping train stop as well as important terminal station. Sealdah–Diamond Harbour line

Budge Budge branch line

Canning branch line

Namkhana branch line

Planned extensions
Multiple new lines and extensions on this section have been planned by the Eastern Railway; however, most remain blocked due to land issues. Budge Budge–Pujali–Uluberia (Birshibpur) line

The  long Budge Budge–Pujali line was sanctioned in the railway budget on 2009-10 while a  extension from Pujali to Birshibpur near Uluberia on the Howrah–Kharagpur line was sanctioned in 2011-12. Once completed this will connect the South Eastern Railway network under Kharagpur division directly with the Majerhat station in the Sealdah South section of the Eastern Railway via a bridge over the Hooghly river. As of 2021, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance. Kalikapur–Ghatakpukur–Minakhan line

In the 2011-12 railway budget, a  long line from Kalikapur on the Canning branch line to Minakhan via Ghatakpukur was sanctioned. However, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance as of 2021. Canning–Jharkhali extension 

A  extension from Canning to Bhangankhali was sanctioned in the 2009-10 railway budget with a railway bridge proposed over the Matla river. In 2011-12 this line was further proposed to be extended by  to Basanti from where another extension of  to Jharkhali was planned to be taken up. However, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance as of 2021. Planned branches to Raidighi and Durgapur

The  long Jaynagar Majilpur–Raidighi line via Krishnachandrapur was sanctioned in 2009-10. In 2011-12 railway budget, a  long new line from Sangrampur on the Sealdah–Diamond Harbour line to Krishnachandrapur was sanctioned along with a  new line from Jaynagar Majilpur to Durgapur. However, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance as of 2021. Namkhana–Chandranagar–Bakkhali extension

The Namkhana branch line was sanctioned to be extended by  to Chandranagar in 2009-10 and then by  km to Bakkhali in 2011-12. However, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance as of 2021. Dankuni–Sagar Island rail line

While there have been multiple proposals to build a railway line to Sagar Island, none have been constructed yet. In 2017, a preliminary survey for a  long line was sanctioned by the Indian Railways in order to boost connectivity between Dankuni and the proposed deep sea port at Sagar Island. The below sections are supposed to be a part of the line if built:

 Pujali–Bankrahat–Diamond Harbour (Gurudasnagar)–Kulpi line: The  Pujali–Bankrahat line and the  Diamond Harbour (Gurudas Nagar)–Bankrahat line were sanctioned in 2011-12 railway budget. The  Diamond Harbour (Gurudas Nagar)–Kulpi line was sanctioned in 2012-13. As of 2021, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance. Kakdwip–Budakholi–Sagar Island line: A  extension from  to Budhakholi was sanctioned in the 2011-12 railway budget with plans to further extend it to Sagar Island via a rail-road bridge. As of 2021, work could not be started on this extension due to non-availability of land and as such the project had been kept under abeyance. 