I'm having trouble with releasing the brakes on Class 40 in van movement services. I follow steps in the manual, change the brake air/vac switch in cab 1, but something is stuck. I did try searching & found nothing. I can get started out of the yard that is opposite Manchester, bc it is flat, but it screeches like brakes are on & needs a lot of power. Later there is a service that starts you on a 1.0%^ grade & I cannot get moving at all, with either the 40, 45, or 47. Please help!