NTES is the salt of Railfanning. IRI is the sugar. - Kirti Solanki

All will be right in next Trial.
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And answer of your query: Two Routes are for sure Delhi-Kolkata and Delhi-Mumbai these two will be fulfilling for intermediates also, just like Delhi-Kolkata will be feeding UP, Bihar, Jharkhand (Patna, Varanasi, Lucknow are considered) and in addition to this there will be a cross connection b/w Mumbai-Kolkata the two Mega-cities. Chennai will also be connected but at present Tracks are not able to bear high speed movements, so Delhi-Chennai Talgo may be delayed.
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I must mention here that government has initiated the Diamond quadrilateral project which will be a high speed corridor connecting all our metros, Delhi-mumbai/kolkata/chennai and kolkata-mumbai/chennai and chennai-mumbai/kolkata.
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I read somewhere that Govt. want to run talgo from Mumbai to Nagpur and then to kolkata.
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In Short these cities are going to have all projects (bullet/Semi HS/ Talgo) for sure: Mumbai, Kolkata, Delhi, Chennai and Intermediate Major cities.