On my way to and from work, I drive either over or under the UP tracks which connect to the Jenks Shop and the freight classification yard here in North Little Rock. Earlier this week, I saw a train which had two "CSX" engines on the front end. On my way to work this morning, I saw another train with three "BNSF" engines. Is UP leasing engines from these other two railroads? Or did they buy these engines and just haven't had time to repaint the engines? Or did UP grant trackage rights to CSX and BNSF through North Little Rock?