There is another reason also for why we need this high speed rail and that too in exactly this region. Sensible Urbanization.
The urbanization that you see in NCR region is funded by financiers based in from Mumbai/Mauritius. Unfortunately except some parts of NCR, the whole of this region is over-supplied. Gurgaon has crashed for all practical purposes. People knew this would be happening since around 2011. As is obvious if you follow UPA styled urbanization based on premium housing that is completely investor driven. In the NCR only the Noida market is working and primarily because it is a user driven market - almost 60% to 70%. Even though even Noida has supply overhang. In Gurgaon people come in only if you have the building completed. Delhi has no user base - people moving out and incoming people prefer rentals. Faridabad is a chor-bazar market with builders simply running away leaving the user in the lurch. Ghaziabad is headless, with its better served areas already sapped out and initial service infrastructure declining by the day. Denouement of Congress system.
New money needs new destination and more capable people with monetary discipline. Only Gujarat can accomodate new money. Only this time you need a big user market. Couple this with the affordable/mid income housing that NDA-2 prefers, you could be seen at least 1 mega city coming up in Gujarat and possibly even 3 cities. If you see the map of Gujarat, then you will see Ahmedabad, Surat, Vadodhara are all on one single axis from the Mumbai route. Straight as the crow flies, Ahmedabad-Mumbai is around 450 Km. For future growth you have Pune also available at one end and Indore at the other end, forming a nice triangle.
Whoever thought out this line has a very long term vision. This will sap the UPA gang of all finances. Bring new finances for new kind into new locations where people have the economic discipline to be able to handle the flux of money. The following policy changes make for potent seeding of future Indian Growth from financial management point of view : High-speed rails + New Housing industry policy + doing away of Equalized Tariff + GST + Land acquisition rationalization.
Only thing missing now is an export economy base for Gujarat and Mumbai axis. Gujjus need to take a business leadership position now. Not just for them selves and their Gujarat, but for the whole country. About 5-10 times bigger in next 15 years of which 10 are guaranteed to be with Modi. And take your next job/business in Gujarat. And rest assured Gujarat will never be allowed to fall in Congress hands. Same gradually going to be true for MP and Maharashtra.
Normally high speed rails do not make sense and higher frequency operation is better but that would be relevant for the rest of India. This region can take the different strategy centered around high speed rail connections. The Airlines business engendered in Gurgaon-Mumbai circuit was much much much bigger a hole than this small but permanent line, capable of giving services far in excess of the so called Civil Aviation industry.