Union Pacific SD70ACe 8881 brings up the rear of train GSFSKI9 08 (Grain Shuttle; Fremont NE to Kaiser CA), which is descending Cajon Pass on the middle main (track 20. Meanwhile, BNSF's California Division Christmas Train (symboled O-SBDSBD2-13A; San Bernardino - Summit - San Bernardino) waits for the the dispatcher to line it onto Track 2 to complete its trip to Summit - at which point the train will reverse direction (with ES44C4 8179 becoming the lead engine) and follow the UP train back to San Bernardino. Saturday, December 13th, was a very busy day on Cajon, and the Christmas train had many, many meets. (UP calls this order of SD70ACe locomotives SD70AH.)