Union Pacific No. 844 steam engine pulling up Weber Canyon has just passed through a tunnel and crossed the Weber River. This location is Exit 108 on I84 called Taggart Exit. Lots of railfans were shooting here. My shot was from a vantage point above the engine - where nobody else thought to go. Weather was overcast, gloomy, and cold. My long johns saved the day. To capture the motion, I used an ISO of 400 to get the shutter speed up to 1/125s at f6.3, thus, the noise seen in the dark areas of the photo. You take what you can get. The drive wheels on this monster are 80 inches tall and, for every turn, the engine moves forward nearly twenty-one feet. If you count the connecting rod revolutions (not that hard) and see five per second, the 844 is travelling 104.7 feet/second or 71.4 mph. Yes, size does matter!