Conflict NMAC
Flight Crew FLC complied w / Automation / Advisory
Airspace Structure; Procedure
Tower advised two aircraft circling Papa John's stadium to remain west of our departure corridor; and one aircraft over downtown to remain east of our departure corridor. Tower controller then issued traffic alerts to us and cleared us for takeoff via the SID. Approximately 1000 FT we received a TCAS warning to maintain vertical speed. I switched to TCAS view on my PFD and it showed us passing directly overhead a target at 400 feet. Traffic was not seen. RA then instructed us to level off momentarily before indicating clear of traffic. In retrospect; I'm not sure if the offending traffic either had time to clear out or misjudged our path; however next time I will be more assertive with the tower to ascertain the locations of the traffic and insuring they are well clear before beginning the takeoff roll.
Widebody pilot reported NMAC departing SDF.