Giving you a Illustrative Example,Refer SS:
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12616 GT From NDLS-MAS. The Pic 1 is the general view,say now if you want to choose BPL as Boarding point click on the train symbol and it will list the halts en-route,then select the BP bhopal or any one you wish...Pic 2 shows you that Bhopal is the BP for you with booking from NDLS-MAS.