It sounds like your loop is about 189" long. In your ~10 second video, the train completes about 3/4 of the loop. That works out to 51,000 inches per hour. The "scale factor" for S-gauge is 64. So it's actually travelling 3.3 million SCALE inches per hour. This equates to 51.5 scale miles per hour.
Think about how your passengers would feel... In real life, passenger trains only achieved those speeds where there were ample straightaways and gentle curves. I guarantee if the loco were shoving a camera car into those curves at that speed, you would get dizzy watching the video. If you want a little more speed, add voltage. Also, make sure your passenger car axles turn freely and have one drop of lubricant on each bearing.
The American Models Pacifics are outstandingly well-engineered locos. There is NOTHING in O gauge outside of Brass that compares. If I could trade, I would. Enjoy the realistic performance your loco has to offer!
