Martin - one other thought. I would recommend checking to make sure your layout (and switch) are level. While I recommended a Ross switch based on your specific circumstances, I myself, use Atlas switches. I had one instance where I was having issues with a switch not throwing all the way in one direction. It seems that over time my layout was no longer level (thanks basement floor..lol) and the weight of trains going over the switch in conjunction with it being no longer level caused the issue. Once I added a shim to level it out, it worked properly. Your issue may have been caused by stresses such as this if not level. You may find it worthwhile to check when you replace the switch.
-Greg
