Just a passing photograph of BNSF 5638 playing rear DPU (along with DASH-9 BNSF 4102) on an eastbound S-LHWLPC1-13 stack train. Captured at Placentia, CA running Main 1 on BNSF's San Bernardino Sub towards Riverside, Barstow, and beyond. BNSF 'AC' traction is all over So Cal now-a-days with the many hundreds of C4 variety GEVOs delivered over the last several years. Still, the older AC4400s have typically been semi rare birds out west. The AC4400 pictured was delivered in May 2003 shortly before the GE's Evolution series began production, while the 4100 series DASH-9 behind it was delivered just 7 months prior in October 2002.