Train Prepares To Stop Shortly After Arriving

A Union Pacific train had a signal aspect I've never seen before. A CSX intermodal prepares to stop soon as it arrives. Sometimes the train prepares to stop before arriving. KCSM had the same signal that I hadn't seen before.

When a train applies the brakes, you'll hear a bang called Slack, the knuckles being stretched out. Trains can't stop on a dime like a car. They take a long time to stop. That's why you don't try to beat them. That's how I knew the train was stopping. Also, you'll hear another bang (slack) right before stopping.