[3] Chennai has a fairly extensive suburban electric multiple unit (EMU) service.

In 1928, work began on constructing two meter gauge (MG) lines connecting the harbour with the southern suburb of Tambaram to run services using steam locomotives.

This was on account of the city's rapid expansion, with largely agricultural areas such as Saidapet, St. Thomas Mount and Tambaram developing into residential quarters.

The trains were painted in dull green with a black wheel base and featured wide sliding doors, a better-designed seating arrangement, and thick glass fronts.

[4] The Madras Electricity Supply Corporation, which powered the railway lines, was aided by sub-stations in Egmore and Meenambakkam.

The running time between Madras Beach and Tambaram stations, which was 2 hours until then, was reduced to 49 minutes.

With the growth in suburban traffic and the existing gauge lacking sufficient carrying capacity, the Indian Railway decided to convert the entire section between Beach and Tambaram, which by then had three MG lines, to BG in early 1991, with a 50:50 joint venture with the state government.

Of the three existing MG lines, two were exclusively used for suburban service and the third one was used for mainline express and passenger trains.

[6] In 1998, further to the Chengleput–Villupuram–Tiruchirapalli gauge conversion project, the railway decided to convert one of the MG lines in the section between Tambaram and Chengleput.

[6] The conversion of the mainline MG line between Egmore and Tambaram began in 2000, resulting in Tambaram station temporarily acting as terminal point for mainline express and passenger trains originally originating from and terminating at Egmore.

Gauge conversion work of two MG lines between Beach and Egmore began in December 2002 and was completed by February 2003.

[6] In February 2003, one of the MG lines between Tambaram and Chengalpet was taken up for conversion and was completed in December 2003, which was used for BG EMU services and by mainline express trains.

[6] In September 2020, the conversion of the third meter-gauge line between Singaperumal Koil and Guduvancherry on the Tambaram–Chengalpattu stretch to broad gauge was completed and opened for traffic.

(along GST Road from St. Thomas Mount to Chengalpattu) Chennai city region stations: Chennai Beach – Chennai Fort – Chennai Park – Chennai Egmore – Chetpet – Nungambakkam – Kodambakkam – Mambalam – Saidapet – Guindy – St. Thomas Mount – Pazhavanthangal – Meenambakkam – Tirisulam – Pallavaram – Chromepet – Tambaram Sanatorium – Tambaram – Perungalathur – Vandalur - Kilambakkam Stations outside Chennai city regions below: Urapakkam – Guduvancheri – Potheri – Kattankulathur – Maraimalai Nagar – Singaperumal Koil – Paranur – Chengalpattu Stations in the South line after Chengalpattu below: Tirumani - Ottivakkam - Padalam - Karunguzhi - Madurantakam - Pakkam - Melmaruvathur - Acharapakkam - Tozhuppedu - Karasangal - Olakur - Panchalam - Tindivanam - Mailam, Perani - Vikravandi - Mundiyampakkam - Villupuram -Valavanur railway station - Chinna Babu Samudram - Villianur and terminates at Puducherry Stations in the South West line after Chengalpattu below: Reddipalayam – Villiambakkam – Palur – Palayaseevaram – Walajabad – Nathapettai – Kanchipuram – Tirumalpur – Takkolam - Arakkonam Chennai Beach – Royapuram - Washermanpet – Chennai Central MMC – Basin Bridge railway station – Vyasarpadi Jeeva – Perambur – Perambur Carriage Works – Perambur Loco Works – Villivakkam – Korattur – Pattaravakkam – Ambattur – Thirumullaivoyal – Annanur – Avadi – Hindu College – Pattabiram – Pattabiram Military Siding – Pattabiram East Depot – Nemilichery – Thiruninravur – Veppampattu – Sevvapet Road – Putlur – Tiruvallur – Egattur – Kadambattur – Senjipanambakkam – Manavur – Thiruvalangadu – Mosur – Puliyamangalam – Arakkonam - Ichiputtur – Tiruttani - Ponpadi - Venkatanarasimharajuvaripeta - Nagari - Ekambarakuppam - Vepagunta - Puttur - Taduku - Sri Venkata Perumal Raju Puram - Pudi - Renigunda - Tiruchanur terminates at Tirupati Jolarpettai - Kettandapatti - Vaniyambadi - Vinnamangalam - Ambur - Pachchakuppam - Melpadi - Valathoor - Mel-Alattur - Gudiyattam - Kavanoor - Virinchipuram - Latteri - Katpadi - Seevur - Thiruvalam railway station - Mukundarayapuram - Walajah Road - Marudhalam - Thalangai railway station - Sholinghur - Mahendravady - Anavardhikhanpettai - Chitteri - Melpakam terminates at Arakkonam Viluppuram - Venkatesapuram - Teli - Mambalapattu - Ayandur - Mugaiyur - Tirukoilur - Adhichchanur - Andampallam - Tandarai - Velanandal - Tiruvannamalai - Turijapuram - Agaram Sibbandi - Polur Arani Road - Sedarampattu - Kannamangalam - Vellore Cantonment - Vellore Town - Katpadi - Seevur - Thiruvalam - Mukundarayapuram - Walajah Road - Marudhalam - Thalangai railway station - Sholinghur - Mahendravady - Anavardhikhanpettai - Chitteri - Melpakam terminates at Arakkonam The MRTS line is an exclusive line of the Chennai suburban railway as it runs elevated for most of its section.

Between Chennai Beach and Park Town, the MRTS alignment runs parallel to the South Suburban line.

The alignment remains elevated till Perungudi beyond which it slopes down to reach the Velachery station which is at grade level.

Stations in Chennai MRTS include Chennai Beach, Chennai Fort, Park Town, Chintadripet, Chepauk, Triplicane, Light House, Mundakanniamman Koil, Thirumayilai, Mandaveli, Greenways Road, Kottupuram, Kasturbai Nagar, Indira Nagar, Tiruvanmiyur, Taramani, Perungudi, Velachery, Puzhuthivakkam (under construction), Adambakkam (under construction), and St. Thomas Mount.

At 232.5 kilometres (144.5 mi), the Chennai Suburban Railway has the longest circular rail route in India.

After finishing the complete the last leg of electrification project Takkolam-Arakkonam stretch, Chennai Beach–Chennai Egmore —Tambaram — Chengalpattu–Kanchipuram–Arakkonam–Tiruvallur–Avadi-vysarpadi Jeeva—washermanpet—Royapuram -Chennai Beach became India's longest circular route.

The newly laid electrified line was inspected by the Commissioner of Railway Safety (CRS) on January 25, 2019, The first train on the circular route ran on 23 April 2019.

Total length of this line from Villivakkam junction to Anna Nagar West railway station is 5 km.

This line started its service at 2003 from Chennai Beach to Anna Nagar West via Royapuram, Villivakkam, and Padi.

Some of the reasons are: Now this line is used by the ICF for trail runs and also used as a parking lots for empty rakes of express trains.

[17] Chennai Central via Vysarpadi Junction and Avadi (destined to any of Pattabiram, Tiruvallur, Kadambattur, Arakkonam, Tirutani and Tirupathi): 90 services of which there are only three fast suburban locals on this route.

All trains have a maximum speed of 100 kilometres per hour (62 mph) and typically run in nine- or 12-coach formations.

Modernised versions of the WAU-4 stock also run on the suburban rail systems of other notable cities like Mumbai, Delhi, Kolkata, Pune and Hyderabad.

[23][24] The suburban network has EMU car sheds at Avadi, Tambaram and Velachery where maintenance of EMUs is done.

Periodical overhauling of electrical rolling stock is done at Perambur Loco Works and the EMU car sheds at Avadi and Tambaram.

[25] On 29 April 2009, a suburban EMU train from Chennai Central suburban terminal was hijacked by an unidentified man, who rammed it with a stationary goods train at Vyasarpadi Jeeva railway station, killing four passengers and injuring 11 others.