At the end of a long journey from Atlanta, the empties CSX E319-21 (Cross,SC-Evansville,IN/EVWR) is pulled up just a few cars short from the rear of the hot "tote" CSX Q154-22 which the outbound crew is doing a job briefing before shooting north up the Chattanooga Sub via of Wauhatchie. The coal bucket will hang back till the "tote" clear the block, and the pair of Tier 4 will pull the train up to the crew change point at the Pike, while the outbound crew is waiting for for it's arrival. Wauhatchie tends to be a busy place at times, and this is in fact a perfect example when everyone arrives at the same time.
Tier IV locomotives are the safest, cleanest, and most fuel efficient locomotives on the rails today. Unfortunately, most of them are ugly and are as quiet as an ACS-64.
