Seeing it takes longer to build a new line than build a new train, and taking into account the situation in India with squatters being able to mount a legal battle that could lead to endless nimby lawsuits, and seeing that on account of their gauge the new trains cannot even be used on existing lines during a transitional period, is it not strange that the ordering of trains is apparently seeing a level of urgency that land acquisiting and construction isn't.
That is mainly because the way it is being designed, land acquisition is being kept to a minimum. In urban areas it is all going to be in bored tunnels, and some on elevated structures on land that is already owned by the railways. In rural areas it will mostly be on elevated structures. There will be very little on ground.
Having said that, yeah they might have some problems, but typically land acquisition in India is not as much a legal problems a political one. Mysteriously, if the local political leaders are on board there typically is very little land acquisition problem from squatters. Somehow the local political leaders figure out a way to dispatch the squatters elsewhere. The wheels of justice indeed turn in strange ways sometimes.