Controlling slack and running a smooth train called on the Engineer's skill with both the brake and the throttle. Slowing down for a speed restriction - for example westbound at Western Avenue crossing the Milwaukee Road - the Engineer would set the big brake on the train, but bail off the engine brake, then reduce the throttle to Run 1. He'd release the brake and hit the diamonds right at 30 mph, then get right after the throttle to pull the train out of the restriction smooth and fast, with no slack action. Eastbound, again the Engineer would reduce the throttle to Run 1, but never to Idle. The old F7's and E's would hang on to transition in Run 1. If the Engineer went to Idle and then opened the throttle again, the locomotive power contactors would drop out, then pick up in series, but drop out again because of speed and then pick up in parallel. While all this was going on, the train was just drifting. When the locomotive finally decided to go to work, it gave the train a pretty good boot.