Metrolink train 643, one of the Orange County shuttle trains, has just arrived from Laguna Niguel/Mission Viejo on Track 4 in Fullerton. Track 4 is used exclusively for these trains that operate between Fullerton and Laguna Niguel/Mission Viejo. BNSF Railway AC4400CW 5647 is on the point, with SCAX MP36PH-3C 891 on the rear. This was during a period in which Metrolink leased a batch of BNSF AC4400CWs because their Korean-built cab cars were having defective plow/pilots upgraded, and these cab cars could not lead on trains in push mode. (Fullerton, California - September 30, 2016)