12567/68 राज्यरानी सुपरफास्ट की धाक राजधानी से कम नहीं है। - Prabhat Sharan

Very intelligent suggestion by Kalyan MP Mr Shrikant Shinde in principle, the final route location is always subject to detailed study of traffic/ technical feasibility.
Firstly the construction as well as property prices of south Mumbai and secondly of Suburban Mumbai are practically stretched to limit, since decades. As a result, the population/ residential colony growth of city shifted to adjacent Municipal area since last 2-decades like Kalyan/ Thane/ Mira Rd-Bhayandar, Vasai-Virar region, Navi Mumbai,Panvel,etc. The growth has now started spreading further outward beyond Kalyan in east, Virar in north, Panvel in south directions. Focus of new intracity travel projects should equally shift from south Mumbai so that current and future growth centers are taken care of with following benefits:
(1) Faster...
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growth of outer areas shall happen, thereby creating effective counter magnets to the fully/already developed crowded areas of Mumbai.
(2) Facilitate ownership of flats to more and more people of Mumbai, due to availability of more affordable housing in the newly developing area. This shall help control the ever burgeoning slums in Mumbai.
(3) Reduce the congestion on the existing overburdened Local trains, as future growth of traffic shall be arrested, and shifted to the new lines serving new growth centres of MMR.
(4) Creating timely local/ metro train infrastructure and facilities shall help in quicker development of residential colonies as well as new commercial centres in the new growth area. This will result in relatively lesser people travelling longer distances in local/Metro trains.