I realize it has been a long time since you asked the question but here goes. All the GE units U25B, U30B, U30BXR we used only on main line through freight trains. They weren't responsive enough and too cumbersome for switching and branch line tracks were usually in too poor a condition for their weight. All of the GE units had recycled ALCO equalizer trucks. Inside brake shoes were a real headache without a pit.