Happy Birthday to me! Well, a day late... Two of BNSF's newest C4's battle upgrade with 8900 tons of manifest ahead of them. As seen through the heatwaves of the DPU's (6602, 6603), the headend (BNSF 6606, 6604, GE Test car, BNSF 7561 and BNSF 4953) grind towards Bena on the famed Tehachapi Pass.