Its not compulsary....mahabodhi bhaut tym pehle se he lhb kr di gayi thi but chennnai exp ko lhb mile kch mahina hua hai....to rsa hota nahi hai....bus kabhi kabhi iska coach usme or uska coach isme lag jata hai...to extend to krna chahiye....idhar se dhanbad or aage se bangalore tk....weekly train hai to problem bho nahi hoga