If you watch the ATCS monitoring at Winslow, it's quite a mess with a lot of trains backed up in both directions waiting for a spot. Mix in the dispatcher bouncing priority trains around stopped trains, there's a lot of "parked" trains waiting to get run around, yarded and crewed and runaround again on the other side of the terminal. I am also going to guess (not so evident by the ATCS display) that there are 14,000ft trains in the mix and don't really clear the running tracks at Winslow. Then throw in the added necessity of flipping the flow of right hand traffic to the left and vice versa and it's heavy duty.