The correct answer is: The speed of the train over neutral section shall not be less than 30 kmph.
A neutral section is a section of track where the rails are not electrified. This means that the train’s motors will not be able to provide power to the wheels, and the train will coast to a stop. In order to prevent the train from coming to a complete stop, the speed of the train over the neutral section must be at least 30 kmph. This will allow the train to coast over the neutral section without coming to a stop.
Option A is incorrect because 20 kmph is not a safe speed for a train to travel over a neutral section. The train could come to a complete stop, which could cause an accident.
Option B is incorrect because 30 kmph is the minimum speed for a train to travel over a neutral section. A train can travel at a higher speed, but it is not required to do so.
Option C is incorrect because 40 kmph is not a safe speed for a train to travel over a neutral section. The train could come to a complete stop, which could cause an accident.
Option D is incorrect because it is not a valid option.