Threading is way around the S-curves on BNSF Railway's "natural crossover" at Frost, just south of Victorville, California, is a baretable train – usually something not very photogenic. But the empty spine cars snaking around the curves has some appeal, as does the pool power in the brief consist. Behind BNSF Dash 9-44CW 5459 is a Kansas City de México ES44AC (KCSM 4872). This train's symbol is B-LPKLAC1-05, a baretable operating from Logistics Park Kansas City KS to Los Angeles CA. Reportedly, this "natural crossover," which allows trains heading to Cajon Pass to cross over for left-hand running when they descend Cajon Pass (the grades work better with left-hand running on Cajon), may be removed soon as this area is slated for triple track. And yet another railroading icon will disappear.