L-3 Communications' security and detection systems division has been selected to provide advanced passenger screening systems for use in the Transportation Security Administration's Transit and Rail Inspection Pilot program. The third phase of the pilot -- to test the feasibility of on-board explosives detection screening of passengers and passenger baggage in rail applications -- begins today at the New Haven, Conn., Union Station. L-3's multiview tomography system was used in Phase I of the trial.    . . .     FLIR Systems Inc. announced it has received orders totaling $7.4 million for infrared (IR) imaging cameras to be used in Northrop Grumman Corp.'s Litening advanced airborne IR targeting and navigation pod. The targeting pods are currently being used in US Air Force B-52 aircraft and certain Air National Guard F-16s. Litening provides real-time, FLIR and CCD imagery to pilots day or night and in adverse weather conditions. FLIR said shipments of the orders have begun and will continue into early 2005.