Railway Diamond Quadrilateral Network

The Diamond Quadrilateral is a project of the Indian railways to establish high speed rail network in India. This quadrilateral will connect the four metro cities in India, i.e. Delhi, Mumbai, Kolkata and Chennai.

Six corridors on Diamond Quadrilateral connecting metropolitan cities and growth centers of the country (Delhi, Mumbai, Chennai & Kolkata) have been identified for feasibility studies for high speed rail connectivity viz:

(i) Delhi-Mumbai

(ii) Mumbai-Chennai

(iii) Chennai-Kolkata

(iv) Kolkata-Delhi

(v) Delhi-Chennai

(vi) Mumbai-Kolkata routes.

Feasibility studies for Delhi-Mumbai, Delhi-Kolkata and Mumbai-Chennai have been awarded in September, 2015.

Feasibility studies for Delhi-Nagpur portion of Delhi-Chennai corridor and Mumbai-Nagpur portion of Mumbai-Kolkata corridor are being undertaken through Government to Government cooperation, with China and Spain respectively.

This project is similar to Golden Quadrilateral which is a roadway project which connects the four metros by Express Ways.


The Golden Quadrilateral falls under National Highways Development Project which has helped to build better road transport in India.

Similarly to improve country’s rail infrastructure there is a need to implement High-speed trains / Bullet trains.

So to fulfill this demand the Diamond Quadrilateral project was planned. India today is planning to start Semi-high speed trains on nine corridors and has ambition to run bullet trains in future.

High-speed train on Mumbai-Ahmedabad section will be the first bullet train corridor to be implemented in the country.

In 2014, the President of India Pranab Mukherjee, officially mentioned that the Government led by Prime Minister Narendra Modi will launch a Diamond Quadrilateral project of high speed trains.