You dont need to dremel it. On the inner rails (which meet at the 'V' plate), you need to either file the end of the rail down where it meets the next piece of track, or sometimes there's just enough slack in the position of the rails that you can move them with a pair of pliers. There needs to be a gap between the inner rails on the switch and the next piece of track for the anti-derail mechanism to work correctly.
I guess you could use a dremel, but you shouldnt have to remove that much material to make the anti-derail work correctly.
