I had the same problem ...
The rails on my Powermatic 68 were just too long for my space and I ordered it that way... go figure? I cut the right side off about 24" or so, here's why. It is basically a heavy duty rip saw, not a cabinet saw in my case. If I need to make panels for cabinets, I have a vertical panel saw. It still has enough right side capacity to do a whole lot of normal woodworking tasks.
If I were you, I'd remove the original rail, use a horizontal metal cutting bandsaw and make an accurate cut. Then If you even decide to add the length back on, make a 2" long steel insert "plug" to align the surfaces while you weld it back on, however, that need may never arise. You could even thread and tap the plug on the bottom and just use socket head cap screws on the bottom rail. Of course, a support would be needed on the length. You will also end up cutting the angle support on the front rail. I moved the sliding pad back on my fence so it rides on the top of the table.
Why not blast the paint and crud off the old rail and replace the measuring tape from a woodworker's supply like Rockler?
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)