With a total distance of 32.13 km (19.96 mi), the line connects Dakshineswar and New Garia and uses 5 ft 6 in (1,676 mm) broad gauge tracks.

As a result, it took nearly 23 years to completely construct around 15 km (9.3 mi) underground railway from Birpara up to Tollygunge.

So metro cars had to be put down on the track near Esplanade by crane, by directly digging the road surface.

But this short portion was not popular and the service was closed down to be restarted when the entire stretch along the north–south corridor was completed.

In 2009, a large number of stations on Blue Line were renamed by then Minister of Railways Mamata Banerjee.

On 21 July 2024, the entire stretch from Dakshineswar to Kavi Subhash, crossed 1.92 lakh passenger mark for the first time on a single day.

Shyambazar, Mahatma Gandhi Road, Esplanade, Kalighat, Rabindra Sarobar & Mahanayak Uttam Kumar stations have connections to the tram network.

Mamata Banerjee during her first tenure as the railway minister initiated the project of Tollygunge – Garia metro extension.

During her second tenure (2009–2011) she inaugurated the extension, and also introduced new Air Conditioned rakes, manufactured indigenously at the Integral Coach Factory.

[7] The stations on this stretch are : Metro construction is of a very complex nature requiring the application of several new technologies in the fields of civil, electrical, signaling and telecommunication engineering.

Indian engineers backed by their own experience and supplemented by their studies abroad adopted advanced technologies in the following fields for the first time in India.

PSD work is proposed for all stations in this line to minimize suicidal cases common in this route.

This plan was proposed after the successful utilization of Platform Screen Doors to keep the number of suicidal cases on the Green Line to absolute zero.

[8] Metro Railway also plans to extend the platform and viaduct of Dakshineswar metro station by ~90 m (300 ft) via erection of two new pillars beyond the current length to facilitate a crossover so that the trains can switch tracks faster in order to increase the frequency of services to the Noapara–Dakshineswar stretch.

The rake was unloaded and taken to Noapara Carshed, after which trial runs and inspection would be carried out before commencing operations.

Some of the issues related to insufficient power to climb up the slopes in the tunnels and higher oscillation in the bogie.

The fleet is unique in that it is the only railroad equipment in India with end-mounted cab doors (except for some of the WAG-6 series locomotives).

[14] This system was found to be ineffective and caused inconvenience for a lot of commuters (including women) and the plan was eventually dropped by the metro authority.