Chennai Metro took less than four years to finish its first 45 km, then, after a short northern extension, waited more than four and a half years for Phase II to open. Phase I ran from the first trains in June 2015 to the last underground stretch in February 2019. Phase II’s first stretch, Poonamallee to Vadapalani, opened on 11 October 2026.
Add the three stages together and the open network is about 68.7 km: 45.046 km of Phase I, 9.05 km of the Washermanpet to Wimco Nagar extension and the 14.6 km Poonamallee stretch. That is still well under the 118.9 km Phase II plan alone.
- Each dot is the day a section opened to passengers, placed to scale along the years 2015 to 2026.
- Orange dots mark the start of Phase I, its completion in 2019 and the first Phase II stretch in 2026.
- The empty space between 2022 and 2026 is the wait for Phase II.
Phase I: five openings in under four years
CMRL’s profile page lists the sequence. Alandur to Koyambedu was commissioned on 29 June 2015; The News Minute reported it as 10 km with seven stations. A state government press release records the 8.6 km Airport to Little Mount elevated stretch, with St Thomas Mount station, opening on 21 September 2016.
The underground sections followed. Thirumangalam to Nehru Park opened on 14 May 2017. Nehru Park to Chennai Central and Saidapet to AG-DMS opened together on 25 May 2018. On 10 February 2019 the AG-DMS to Washermanpet stretch opened, completing Phase I’s 45 km. CMRL gives the two Phase I corridors as 23.085 km and 21.961 km, with 32 stations.
The northern extension, in two steps
The 9.05 km extension from Washermanpet to Wimco Nagar opened on 14 February 2021, but two of its nine stations, Thiruvottriyur Theradi and Wimco Nagar Depot, were not ready. CMRL says they were commissioned on 13 March 2022. Joined to Corridor 1, the extension makes a single line of about 32.1 km from Wimco Nagar Depot to the Airport.
The gap between the last extension stations in March 2022 and the first Phase II stretch in October 2026, the longest pause in the network’s growth so far. Dates from CMRL and All India Radio.
Phase II: the first 14.6 km of 118.9
CMRL’s Phase II page describes three corridors: Madhavaram to SIPCOT (45.8 km), Lighthouse to Poonamallee Bypass (26.1 km) and Madhavaram to Sholinganallur (47.0 km). On 11 October 2026 the Prime Minister inaugurated the 14.6 km Poonamallee to Vadapalani section of Corridor 4, which All India Radio reported ahead of the event. DT Next lists 11 stations on it, and Swarajya described it as the first part of Phase II cleared for passengers.
The scale chart shows how much is still to come. Corridors 3 and 5 are each longer than the whole of Phase I, and neither has an open stretch yet.
The numbers behind the graphic
| Date opened | Section | Length |
|---|---|---|
| 29 June 2015 | Alandur to Koyambedu | 10 km |
| 21 September 2016 | Airport to Little Mount (and St Thomas Mount station) | 8.6 km |
| 14 May 2017 | Thirumangalam to Nehru Park | not stated |
| 25 May 2018 | Nehru Park to Chennai Central; Saidapet to AG-DMS | not stated |
| 10 February 2019 | AG-DMS to Washermanpet (Phase I complete) | Phase I total 45.046 km |
| 14 February 2021 | Washermanpet to Wimco Nagar (7 of 9 stations) | 9.05 km |
| 13 March 2022 | Thiruvottriyur Theradi, Wimco Nagar Depot stations | part of 9.05 km |
| 11 October 2026 | Poonamallee to Vadapalani (Corridor 4) | 14.6 km |
| Not yet open | Corridor 3 Madhavaram to SIPCOT | 45.8 km |
| Partly open | Corridor 4 Lighthouse to Poonamallee Bypass | 26.1 km (11.5 km not yet open) |
| Not yet open | Corridor 5 Madhavaram to Sholinganallur | 47.0 km |
Source: CMRL company profile and Phase II project status pages (updated November and December 2025); Government of Tamil Nadu press release, 21 September 2016; All India Radio (October 2026); The News Minute (June 2015). Open network = 45.046 + 9.05 + 14.6 km.
About the data
Opening dates and corridor lengths come from Chennai Metro Rail’s own pages, which were last updated in late 2025 and do not yet list the October 2026 opening. For that stretch we used All India Radio’s report of 14.6 km; some reports round it to 15 km. CMRL does not publish lengths for each Phase I opening, so only the 2015 and 2016 sections have their own lengths here, and the timeline is not a chart of cumulative kilometres.
The length still to open on Corridor 4 (11.5 km) is our subtraction of 14.6 from 26.1. CMRL’s Phase II page projected completion by the end of 2028; we have not shown that as a date because it is a target.
Quick answers
When did Chennai Metro start running?
The first section, Alandur to Koyambedu, was commissioned on 29 June 2015, according to CMRL.
How long is the Chennai Metro network now?
About 68.7 km is open after October 2026: Phase I (45.046 km), the Wimco Nagar extension (9.05 km) and Poonamallee to Vadapalani (14.6 km).
Which was the first Phase II stretch to open?
Poonamallee to Vadapalani on Corridor 4, inaugurated on 11 October 2026.
Information checked against official sources on 21 October 2026. Figures can be revised; confirm on the linked official pages before relying on them.
Sources
- CMRL profile (Chennai Metro Rail Limited)
- Project status, Phase II (Chennai Metro Rail Limited)
- Press release on Airport to Little Mount metro, 21 September 2016 (Government of Tamil Nadu)
- PM to inaugurate metro and railway projects in Chennai on October 11 (All India Radio News)
- Vadapalani to Poonamallee Metro: station list and timings (DT Next)
- Chennai Metro Phase II to get its first operational corridor (Swarajya)
- Chennai Metro Rail gets inaugurated (The News Minute)
