I came across a repair crew at Foley Blvd in Coon Rapids fixing a broken gate arm. I only had my cell phone to take videos but caught several trains needing to flag their train across. (I have some other videos on my youtube page). This BNSF loco gets jerked back, why? My presumption is that the brake was set on the cars while the Loco moved. I this common or just an error?

http://www.youtube.com/watch?v=VwDJciIassg

That is a fairly common occurence. The air brakes on railroad equipment don't release fast, so they started taking a pull on the train, but the brakes weren't fully released. I see it all the time.

Dan