The Indian Railways' Golden quadrilateral linking the four metropolitan cities of Delhi, Mumbai, Chennai and Howrah, and its two diagonals (Delhi-Chennai and Mumbai-Howrah) comprises of 16% of the route but carry more than 52% of the passenger traffic and 58% of revenue earning freight traffic of IR. This trunk route is highly saturated with line capacity utilization varying between 115% to 150%.
Over the year, Railways lost the share in freight traffic from 88% in 1950-51 to 26% in 2021-22. Not only this, the National highways along these corridors comprising 0.5% of the road network carried almost 40% of the road freight.