Climbing Zarley's Hill. UP AC4400CW #6310 is in charge of INPG4X, an extra intermodal/double stack train from North Platte, as it makes its way up Zarley's Hill in Joliet. At the present time, 6310 is one of five AC4400CW's left in Southern Pacific paint. If I were a betting man, I'd say this unit has passed this location more than a few times during its days as the SP 264.
