having an exceptional record with the NCR, i am now going to work for the Legion. i started this quest by speaking with Curtis, got all the necessary bomb framing materials from the trash can (all of them, double & triple checked), put them in Crenshaws locker (double & triple checked that all were placed in), killed Crenshaw, could not engage Hsu in any advancing dialogue, just the same 5 (?) questions/answers about the NCR, & the dam & so forth. Reported back to Curtis, put the bomb on the monorail, heard the message on the monorail about everyone must leave, train going to depart, etc., followed the quest directions about exiting the monorail & watch it explode. well. nothing happens and the quest cannont advance. tried going to the LVB building on the strip and taking the monorail back to McCarran and getting off there, but still lack of response/action. tried doing the quest in a different order, putting the bomb on the train first & then framing Crenshaw, nothing. not sure what needs to be done. please please help!