Bullet or high speed railways are a way to stop the high class passengers who are only profitable component revenue from switching over to Airlines. As airlines get cheaper and AC travel gets costlier it will happen. HSR is last option to stop them that may not be successful as it will be costly to make and run. But is very good for brand building and attracting FDI. For Railways sleeper travel is only one to go on for long time as smaller routes are eaten up by volvos and longer by flights.