Russ theres a few ways to do this, I usually use an air ipact wrench and penetrateing oil to get the pads off of salvagable chains/rails. When i need to get the pads off a set of worn out rails Ill use the impact wrench but if they are stubborn i'll stop with that and use the torch. My new favorite toy is a gouging tip in my friends plasma cutter for the stubborn ones. I have taken them down and swapped them with a breaker bar but it takes too long. I change the pads out on a dozer last week in about 3 hours with some stubborn bolts. I had lots of oil and my impact wrench handy.