I don't think T-18 will run at 160 kmph, it'll be limited to run at 130 kmph if introduced. This is done as part of IR's modernisation plans, the main goal for the IR in this whole T-18 and T-20 development is gaining the technological know-how to build a high speed train with self propulsion. This is not something that want radically change the IR's trains running now. It is probably towards knowing how to build a high speed, futuristic and top of the line trains, so that when the time comes to invest in the modernisation of the whole IR, we don't look out to foreign nations and companies to supply us with rakes or train sets and technology to build new trains. This is some small price to pay to gain the more important Intellectual Property and technology to build the trains for ourselves. This might be a small...
more... step in the upgradation plan of next 50 years or a century. Most of the world doesn't use broad gauge as well, so developing a train by ourselves would always be a plus.