i dont know why indian railway have diffrent superfast charges for different class its 30 for sleeper and 75 for AC first class. sf charge related to speed not to a particular class .......... All coaches attached in single train and they all run with same speed ........ its injustice to passanger ,,,,,,,,, if railway cant review sf charge ...... tab unko AC coach ko alag karke 100 ki speed se chalana chahiye .................